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DTSTART;TZID=America/New_York:20230321T170000
DTEND;TZID=America/New_York:20230321T180000
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SUMMARY:2023 Ding Shum Lecture
DESCRIPTION:On March 21\, 2023\, the CMSA hosted the fourth annual Ding Shum Lecture\, given by Cynthia Dwork (Harvard SEAS and Microsoft Research). \n\n\nTime: 5:00-6:00 pm ET \nLocation: Harvard University Science Center Hall D \nThis event was be held in person and via Zoom webinar. \n\n  \n\nTitle: Measuring Our Chances: Risk Prediction in This World and its Betters \nAbstract: Prediction algorithms score individuals\, assigning a number between zero and one that is often interpreted as an individual probability: a 0.7 “chance” that this child is in danger in the home; an 80% “probability” that this woman will succeed if hired; a 1/3 “likelihood” that they will graduate within 4 years of admission. But what do words like “chance\,” “probability\,” and “likelihood” actually mean for a non-repeatable activity like going to college? This is a deep and unresolved problem in the philosophy of probability. Without a compelling mathematical definition we cannot specify what an (imagined) perfect risk prediction algorithm should produce\, nor even how an existing algorithm should be evaluated. Undaunted\, AI and machine learned algorithms churn these numbers out in droves\, sometimes with life-altering consequences. \nAn explosion of recent research deploys insights from the theory of pseudo-random numbers – sequences of 0’s and 1’s that “look random” but in fact have structure – to yield a tantalizing answer to the evaluation problem\, together with a supporting algorithmic framework with roots in the theory of algorithmic fairness. \nWe can aim even higher. Both (1) our qualifications\, health\, and skills\, which form the inputs to a prediction algorithm\, and (2) our chances of future success\, which are the desired outputs from the ideal risk prediction algorithm\, are products of our interactions with the real world. But the real world is systematically inequitable. How\, and when\, can we hope to approximate probabilities not in this world\, but in a better world\, one for which\, unfortunately\, we have no data at all? Surprisingly\, this novel question is inextricably bound with the very existence of nondeterminism. \n\n\nProfessor Cynthia Dwork is Gordon McKay Professor of Computer Science at the Harvard University John A. Paulson School of Engineering and Applied Sciences\, Affiliated Faculty at Harvard Law School\, and Distinguished Scientist at Microsoft. She uses theoretical computer science to place societal problems on a firm mathematical foundation. \nHer recent awards and honors include the 2020 ACM SIGACT and IEEE TCMF Knuth Prize\, the 2020 IEEE Hamming Medal\, and the 2017 Gödel Prize. \n\n\n\n\nTalk Chair: Horng-Tzer Yau (Harvard Mathematics & CMSA)\n\nModerator: Faidra Monachou (Harvard CMSA)\n\n\n\n\n\n\n\n\n\nThe 2020-2022 Ding Shum lectures were postponed due to Covid-19. \n\n\n\nThe 2019 Ding Shum Lecture featured Ronald Rivest on “Election Security.”\n\n\nThis event is made possible by the generous funding of Ding Lei and Harry Shum. \n\n\nWatch the Lecture on Youtube:
URL:https://cmsa.fas.harvard.edu/event/2023-ding-shum-lecture/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Ding Shum Lecture,Event,Special Lectures
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230324T163000
DTEND;TZID=America/New_York:20230324T180000
DTSTAMP:20260716T055601
CREATED:20230705T053823Z
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SUMMARY:CMSA/MATH Bi-Annual Gathering
DESCRIPTION:On Friday\, March 24th\, 4:30PM – 6PM\, the CMSA will host the CMSA/MATH Bi-Annual Gathering for Harvard CMSA and Math affiliates in the Common Room at 20 Garden Street\, Cambridge MA 02138.
URL:https://cmsa.fas.harvard.edu/event/cmsa-math-bi-annual-gathering/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230407T140000
DTEND;TZID=America/New_York:20230408T170000
DTSTAMP:20260716T055601
CREATED:20230705T055126Z
LAST-MODIFIED:20240229T095034Z
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SUMMARY:Current Developments in Mathematics Conference 2023
DESCRIPTION:Current Developments in Mathematics 2023\nHarvard University Science Center\, Lecture Hall C\nApril 7-8\, 2023\nSpeakers: \nAmol Aggarwal – Columbia University\nBhargav Bhatt – Institute for Advanced Study\, Princeton University\, & University of Michigan\nPaul Bourgade – New York University\, Courant Institute\nVesselin Dimitrov – Institute for Advanced Study & Georgia Institute of Technology\nGreta Panova – University of Southern California\n\n\n\n\nFor more information\, and to register\, please visit:\nCurrent Developments in Mathematics 2023 \n \n  \nOrganizers: David Jerison\, Paul Seidel\, Nike Sun (MIT); Denis Auroux\, Mark Kisin\, Lauren Williams\, Horng-Tzer Yau \nSponsored by the National Science Foundation\, Harvard University Mathematics\, Harvard University Center of Mathematical Sciences and Applications\, and the Massachusetts Institute of Technology. \nHarvard University is committed to maintaining a safe and healthy educational and work environment in which no member of the University community is\, on the basis of sex\, sexual orientation\, or gender identity\, excluded from participation in\, denied the benefits of\, or subjected to discrimination in any University program or activity. More information can be found here.
URL:https://cmsa.fas.harvard.edu/event/cdm-2023/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Conference,Event
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CDM-2023-Poster.png
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DTSTART;TZID=America/New_York:20230507T090000
DTEND;TZID=America/New_York:20230512T180000
DTSTAMP:20260716T055601
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SUMMARY:Workshop on Global Categorical Symmetries
DESCRIPTION:The CMSA will be hosting a Workshop on Global Categorical Symmetries from May 7 – 12\, 2023 \nParticipation in the workshop is by invitation. \nPublic Lectures \nThere will be three lectures on Thursday\, May 11\, 2023\, which are open to the public.\nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138\nNote: The public lectures will be held in-person only. \n2:00 – 2:50 pm\nSpeaker: Kantaro Ohmori (U Tokyo )\nTitle: Fusion Surface Models: 2+1d Lattice Models from Higher Categories\nAbstract: Generalized symmetry in general dimensions is expected to be described by higher categories. Conversely\, one might expect that\, given a higher category with appropriate structures\, there exist models that admit the category as its symmetry. In this talk I will explain a construction of such 2+1d lattice models for fusion 2-categories defined by Douglas and Reutter\, generalizing the work of Aasen\, Fendley and Mong on anyon chains. The construction is by decorating a boundary of a topological Freed-Teleman-Moore sandwich into a non-topological boundary. In particular we can construct a family of candidate lattice systems for chiral topological orders. \n  \n3:00 – 3:50 pm\nSpeaker: David Jordan (Edinburgh)\nTitle: Langlands duality for 3-manifolds\nAbstract: Originating in number theory\, and permeating representation theory\, algebraic geometry\, and quantum field theory\, Langlands duality is a pattern of predictions relating pairs of mathematical objects which have no clear a priori mathematical relation. In this talk I’ll explain a new conjectural appearance of Langlands duality in the setting of 3-manifold topology\, I’ll give some evidence in the form of special cases\, and I’ll survey how the conjecture relates to both the arithmetic and geometric Langlands duality conjectures. \n3:50 – 4:30 pm\nTea/Snack Break \n4:30 – 5:30 pm\nSpeaker: Ken Intriligator (UCSD)\nColloquium\nTitle: QFT Aspects of Symmetry\nAbstract: Everything in the Universe\, including the photons that we see and the quarks and electrons in our bodies\, are actually ripples of quantum fields. Quantum field theory (QFT) is the underlying mathematical framework of Nature\, and in the case of electrons and photons it is the most precisely tested theory in science. Strongly coupled aspects\, e.g. the confinement of quarks and gluons at long distances\, remain challenging. QFT also describes condensed matter systems\, connects to string theory and quantum gravity\, and describes cosmology. Symmetry has deep and powerful realizations and implications throughout physics\, and this is especially so for the study of QFT. Symmetries play a helpful role in characterizing the phases of theories and their behavior under renormalization group flows (zooming out). Quantum field theory has also been an idea generating machine for mathematics\, and there has been increasingly fruitful synergy in both directions. We are currently exploring the symmetry-based interconnections between QFT and mathematics in our Simons Collaboration on Global Categorical Symmetry\, which is meeting here this week. I will try to provide an accessible\, colloquium-level introduction to aspects of symmetries and QFT\, both old and new.
URL:https://cmsa.fas.harvard.edu/event/globalcomputing23/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Workshop
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230516T090000
DTEND;TZID=America/New_York:20230519T170000
DTSTAMP:20260716T055601
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SUMMARY:GRAMSIA: Graphical Models\, Statistical Inference\, and Algorithms
DESCRIPTION:On May 16 – May 19\, 2023 the CMSA hosted a four-day workshop on GRAMSIA: Graphical Models\, Statistical Inference\, and Algorithms. The workshop was held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. This workshop was organized by David Gamarnik (MIT)\, Kavita Ramanan (Brown)\, and Prasad Tetali  (Carnegie Mellon). \nThe purpose of this workshop is to highlight various mathematical questions and issues associated with graphical models and message-passing algorithms\, and to bring together a group of researchers for discussion of the latest progress and challenges ahead. In addition to the substantial impact of graphical models on applied areas\, they are also connected to various branches of the mathematical sciences. Rather than focusing on the applications\, the primary goal is to highlight and deepen these mathematical connections. \nLocation: Room G10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \n  \nSpeakers:\n\nJake Abernethy (Georgia Tech)\nGuy Bresler (MIT)\nFlorent Krzakala (Ecole Polytechnique Federale de Lausanne)\nLester Mackey (Microsoft Research New England)\nTheo McKenzie (Harvard)\nAndrea Montanari (Stanford)\nElchanan Mossel (MIT)\nYury Polyanskiy (MIT)\nPatrick Rebeschini (Oxford)\nSubhabrata Sen (Harvard)\nDevavrat Shah (MIT)\nPragya Sur (Harvard)\nAlex Wein (UC Davis)\nYihong Wu (Yale)\nSarath Yasodharan (Brown)\nHorng-Tzer Yau (Harvard)\nChristina Lee Yu (Cornell)\nIlias Zadik (MIT)\n\nSchedule:\nTuesday\, May 16\, 2023 \n\n\n\n9:00 am\nBreakfast\n\n\n9:15 – 9:30 am\nIntroductory remarks by organizers\n\n\n9:30 – 10:20 am\nSubhabrata Sen (Harvard) \nTitle: Mean-field approximations for high-dimensional Bayesian regression \nAbstract: Variational approximations provide an attractive computational alternative to MCMC-based strategies for approximating the posterior distribution in Bayesian inference. The Naive Mean-Field (NMF) approximation is the simplest version of this strategy—this approach approximates the posterior in KL divergence by a product distribution. There has been considerable progress recently in understanding the accuracy of NMF under structural constraints such as sparsity\, but not much is known in the absence of such constraints. Moreover\, in some high-dimensional settings\, the NMF is expected to be grossly inaccurate\, and advanced mean-field techniques (e.g. Bethe approximation) are expected to provide accurate approximations. We will present some recent work in understanding this duality in the context of high-dimensional regression. This is based on joint work with Sumit Mukherjee (Columbia) and Jiaze Qiu (Harvard University).\n\n\n10:30 – 11:00 am\nCoffee break  \n\n\n11:00 – 11:50 am\nElchanan Mossel (MIT) \nTitle: Some modern perspectives on the Kesten-Stigum bound for reconstruction on trees. \nAbstract: The Kesten-Stigum bound is a fundamental spectral bound for reconstruction on trees. I will discuss some conjectures and recent progress on understanding when it is tight as well as some conjectures and recent progress on what it signifies even in cases where it is not tight.\n\n\n12:00 – 2:00 pm\nLunch\n\n\n2:00 – 2:50 pm\nChristina Lee Yu (Cornell) \nTitle: Exploiting Neighborhood Interference with Low Order Interactions under Unit Randomized Design \nAbstract: Network interference\, where the outcome of an individual is affected by the treatment assignment of those in their social network\, is pervasive in many real-world settings. However\, it poses a challenge to estimating causal effects. We consider the task of estimating the total treatment effect (TTE)\, or the difference between the average outcomes of the population when everyone is treated versus when no one is\, under network interference. Under a Bernoulli randomized design\, we utilize knowledge of the network structure to provide an unbiased estimator for the TTE when network interference effects are constrained to low order interactions among neighbors of an individual. We make no assumptions on the graph other than bounded degree\, allowing for well-connected networks that may not be easily clustered. Central to our contribution is a new framework for balancing between model flexibility and statistical complexity as captured by this low order interactions structure.\n\n\n3:00 – 3:30 pm\nCoffee break \n\n\n3:30 – 4:20 pm\nTheo McKenzie (Harvard) \nTitle: Spectral statistics for sparse random graphs \nAbstract: Understanding the eigenvectors and eigenvalues of the adjacency matrix of random graphs is fundamental to many algorithmic questions; moreover\, it is related to longstanding questions in quantum physics. In this talk we focus on random models of sparse graphs\, giving some properties that are unique to these sparse graphs\, as well as some specific obstacles. Based on this\, we show some new results on spectral statistics of sparse random graphs\, as well as some conjectures.\n\n\n4:40 – 6:30 pm\nLightning talk session + welcome reception\n\n\n\n  \nWednesday\, May 17\, 2023 \n\n\n\n9:00 am\nBreakfast\n\n\n9:30 – 10:20\nIlias Zadik (MIT) \nTitle: Revisiting Jerrum’s Metropolis Process for the Planted Clique Problem \nAbstract: Jerrum in 1992 (co-)introduced the planted clique model by proving the (worst-case initialization) failure of the Metropolis process to recover any o(sqrt(n))-sized clique planted in the Erdos-Renyi graph G(n\,1/2). This result is classically cited in the literature of the problem\, as the “first evidence” the o(sqrt(n))-sized planted clique recovery task is “algorithmically hard”.\nIn this work\, we show that the Metropolis process actually fails to work (under worst-case initialization) for any o(n)-sized planted clique\, that is the failure applies well beyond the sqrt(n) “conjectured algorithmic threshold”. Moreover we also prove\, for a large number of temperature values\, that the Metropolis process fails also under “natural initialization”\, resolving an open question posed by Jerrum in 1992.\n\n\n10:30 – 11:00\nCoffee break\n\n\n11:00 – 11:50\nFlorent Krzakala (Ecole Polytechnique Federale de Lausanne) \nTitle: Are Gaussian data all you need for machine learning theory? \nAbstract: Clearly\, no! Nevertheless\, the Gaussian assumption remains prevalent among theoreticians\, particularly in high-dimensional statistics and physics\, less so in traditional statistical learning circles. To what extent are Gaussian features merely a convenient choice for certain theoreticians\, or genuinely an effective model for learning? In this talk\, I will review recent progress on these questions\, achieved using rigorous probabilistic approaches in high-dimension and techniques from mathematical statistical physics. I will demonstrate that\, despite its apparent limitations\, the Gaussian approach is sometimes much closer to reality than one might expect. In particular\, I will discuss key findings from a series of recent papers that showcase the Gaussian equivalence of generative models\, the universality of Gaussian mixtures\, and the conditions under which a single Gaussian can characterize the error in high-dimensional estimation. These results illuminate the strengths and weaknesses of the Gaussian assumption\, shedding light on its applicability and limitations in the realm of theoretical statistical learning.\n\n\n12:00 – 2:00 pm\nLunch\n\n\n2:00 – 2:50 pm\nAndrea Montanari (Stanford) \nTitle: Dimension free ridge regression \nAbstract: Random matrix theory has become a widely useful tool in high-dimensional statistics and theoretical machine learning. However\, random matrix theory is largely focused on the proportional asymptotics in which the number of columns grows proportionally to the number of rows of the data matrix. This is not always the most natural setting in statistics where columns correspond to covariates and rows to samples. With the objective to move beyond the proportional asymptotics\, we revisit ridge regression. We allow the feature vector to be high-dimensional\, or even infinite-dimensional\, in which case it belongs to a separable Hilbert space and assume it to satisfy a certain convex concentration property. Within this setting\, we establish non-asymptotic bounds that approximate the bias and variance of ridge regression in terms of the bias and variance of an ‘equivalent’ sequence model (a regression model with diagonal design matrix). Previously\, such an approximation result was known only in the proportional regime and only up to additive errors: in particular\, it did not allow to characterize the behavior of the excess risk when this converges to 0. Our general theory recovers earlier results in the proportional regime (with better error rates). As a new application\, we obtain a completely explicit and sharp characterization of ridge regression for Hilbert covariates with regularly varying spectrum. Finally\, we analyze the overparametrized near-interpolation setting and obtain sharp ‘benign overfitting’ guarantees. \n[Based on joint work with Chen Cheng]\n\n\n3:00 – 3:50 pm\nYury Polyanskiy (MIT) \nTitle: Recent results on broadcasting on trees and stochastic block model \nAbstract: I will survey recent results and open questions regarding the q-ary stochastic block model and its local version (broadcasting on trees\, or BOT). For example\, establishing uniqueness of non-trivial solution to distribution recursions (BP fixed point) implies a characterization for the limiting mutual information between the graph and community labels. For q=2 uniqueness holds in all regimes. For q>2 uniqueness is currently only proved above a certain threshold that is asymptotically (for large q) is close to Kesten-Stigum (KS) threshold. At the same time between the BOT reconstruction and KS we show that uniqueness does not hold\, at least in the presence of (arbitrary small) vertex-level side information. I will also discuss extension of the robust reconstruction result of Janson-Mossel’2004. \nBased on joint works with Qian Yu (Princeton) and Yuzhou Gu (MIT).\n\n\n4:00 – 4:30 pm\nCoffee break \n\n\n4:30 – 5:20 pm\nAlex Wein (UC Davis) \nTitle: Is Planted Coloring Easier than Planted Clique? \nAbstract: The task of finding a planted clique in the random graph G(n\,1/2) is perhaps the canonical example of a statistical-computational gap: for some clique sizes\, the task is statistically possible but believed to be computationally hard. Really\, there are multiple well-studied tasks related to the planted clique model: detection\, recovery\, and refutation. While these are equally difficult in the case of planted clique\, this need not be true in general. In the related planted coloring model\, I will discuss the computational complexity of these three tasks and the interplay among them. Our computational hardness results are based on the low-degree polynomial model of computation.By taking the complement of the graph\, the planted coloring model is analogous to the planted clique model but with many planted cliques. Here our conclusion is that adding more cliques makes the detection problem easier but not the recovery problem.\n\n\n\n  \nThursday\, May 18\, 2023 \n\n\n\n9:00\nBreakfast\n\n\n9:30 – 10:20\nGuy Bresler (MIT) \nTitle: Algorithmic Decorrelation and Planted Clique in Dependent Random Graphs \nAbstract: There is a growing collection of average-case reductions starting from Planted Clique (or Planted Dense Subgraph) and mapping to a variety of statistics problems\, sharply characterizing their computational phase transitions. These reductions transform an instance of Planted Clique\, a highly structured problem with its simple clique signal and independent noise\, to problems with richer structure. In this talk we aim to make progress in the other direction: to what extent can these problems\, which often have complicated dependent noise\, be transformed back to Planted Clique? Such a bidirectional reduction between Planted Clique and another problem shows a strong computational equivalence between the two problems.  We develop a new general framework for reasoning about the validity of average-case reductions based on low sensitivity to perturbations. As a concrete instance of our general result\, we consider the planted clique (or dense subgraph) problem in an ambient graph that has dependent edges induced by randomly adding triangles to the Erdos-Renyi graph G(n\,p)\, and show how to successfully eliminate dependence by carefully removing the triangles while approximately preserving the clique (or dense subgraph). Joint work with Chenghao Guo and Yury Polyanskiy.\n\n\n10:30 – 11:00\nCoffee break  \n\n\n11:00 – 11:50\nSarath Yasodharan (Brown) \nTitle: A Sanov-type theorem for unimodular marked random graphs and its applications \nAbstract: We prove a Sanov-type large deviation principle for the component empirical measures of certain sequences of unimodular random graphs (including Erdos-Renyi and random regular graphs) whose vertices are marked with i.i.d. random variables. Specifically\, we show that the rate function can be expressed in a fairly tractable form involving suitable relative entropy functionals. As a corollary\, we establish a variational formula for the annealed pressure (or limiting log partition function) for various statistical physics models on sparse random graphs. This is joint work with I-Hsun Chen and Kavita Ramanan.\n\n\n12:00 – 12:15 pm \n12:15 – 2:00 pm\nGroup Photo  \nLunch \n\n\n2:00 – 2:50 pm\nPatrick Rebeschini (Oxford) \nTitle: Implicit regularization via uniform convergence \nAbstract: Uniform convergence is one of the main tools to analyze the complexity of learning algorithms based on explicit regularization\, but it has shown limited applicability in the context of implicit regularization. In this talk\, we investigate the statistical guarantees on the excess risk achieved by early-stopped mirror descent run on the unregularized empirical risk with the squared loss for linear models and kernel methods. We establish a direct link between the potential-based analysis of mirror descent from optimization theory and uniform learning. This link allows characterizing the statistical performance of the path traced by mirror descent directly in terms of localized Rademacher complexities of function classes depending on the choice of the mirror map\, initialization point\, step size\, and the number of iterations. We will discuss other results along the way.\n\n\n3:00 – 3:50 pm\nPragya Sur (Harvard) \nTitle: A New Central Limit Theorem for the Augmented IPW estimator in high dimensions \nAbstract: Estimating the average treatment effect (ATE) is a central problem in causal inference. Modern advances in the field studied estimation and inference for the ATE in high dimensions through a variety of approaches. Doubly robust estimators such as the augmented inverse probability weighting (AIPW) form a popular approach in this context. However\, the high-dimensional literature surrounding these estimators relies on sparsity conditions\, either on the outcome regression (OR) or the propensity score (PS) model. This talk will introduce a new central limit theorem for the classical AIPW estimator\, that applies agnostic to such sparsity-type assumptions. Specifically\, we will study properties of the cross-fit version of the estimator under well-specified OR and PS models\, and the proportional asymptotics regime where the number of confounders and sample size diverge proportional to each other. Under assumptions on the covariate distribution\, our CLT will uncover two crucial phenomena among others: (i) the cross-fit AIPW exhibits a substantial variance inflation that can be quantified in terms of the signal-to-noise ratio and other problem parameters\, (ii) the asymptotic covariance between the estimators used while cross-fitting is non-negligible even on the root-n scale. These findings are strikingly different from their classical counterparts\, and open a vista of possibilities for studying similar other high-dimensional effects. On the technical front\, our work utilizes a novel interplay between three distinct tools—approximate message passing theory\, the theory of deterministic equivalents\, and the leave-one-out approach.\n\n\n4:00 – 4:30 pm\nCoffee break \n\n\n4:30 – 5:20 pm\nYihong Wu (Yale) \nTitle: Random graph matching at Otter’s threshold via counting chandeliers\n\nAbstract: We propose an efficient algorithm for graph matching based on similarity scores constructed from counting a certain family of weighted trees rooted at each vertex. For two Erdős–Rényi graphs G(n\,q) whose edges are correlated through a latent vertex correspondence\, we show that this algorithm correctly matches all but a vanishing fraction of the vertices with high probability\, provided that nq\to\infty and the edge correlation coefficient ρ satisfies ρ^2>α≈0.338\, where α is Otter’s tree-counting constant. Moreover\, this almost exact matching can be made exact under an extra condition that is information-theoretically necessary. This is the first polynomial-time graph matching algorithm that succeeds at an explicit constant correlation and applies to both sparse and dense graphs. In comparison\, previous methods either require ρ=1−o(1) or are restricted to sparse graphs. The crux of the algorithm is a carefully curated family of rooted trees called chandeliers\, which allows effective extraction of the graph correlation from the counts of the same tree while suppressing the undesirable correlation between those of different trees. This is joint work with Cheng Mao\, Jiaming Xu\, and Sophie Yu\, available at https://arxiv.org/abs/2209.12313\n\n\n\n  \nFriday\, May 19\, 2023 \n\n\n\n9:00\nBreakfast\n\n\n9:30 – 10:20\nJake Abernethy (Georgia Tech) \nTitle: Optimization\, Learning\, and Margin-maximization via Playing Games \nAbstract: A very popular trick for solving certain types of optimization problems is this: write your objective as the solution of a two-player zero-sum game\, endow both players with an appropriate learning algorithm\, watch how the opponents compete\, and extract an (approximate) solution from the actions/decisions taken by the players throughout the process. This approach is very generic and provides a natural template to produce new and interesting algorithms. I will describe this framework and show how it applies in several scenarios\, including optimization\, learning\, and margin-maximiation problems. Along the way we will encounter a number of novel tools and rediscover some classical ones as well.\n\n\n10:30 – 11:00\nCoffee break  \n\n\n11:00 – 11:50\nDevavrat Shah (MIT) \nTitle: On counterfactual inference with unobserved confounding via exponential family \nAbstract: We are interested in the problem of unit-level counterfactual inference with unobserved confounders owing to the increasing importance of personalized decision-making in many domains: consider a recommender system interacting with a user over time where each user is provided recommendations based on observed demographics\, prior engagement levels as well as certain unobserved factors. The system adapts its recommendations sequentially and differently for each user. Ideally\, at each point in time\, the system wants to infer each user’s unknown engagement if it were exposed to a different sequence of recommendations while everything else remained unchanged. This task is challenging since: (a) the unobserved factors could give rise to spurious associations\, (b) the users could be heterogeneous\, and (c) only a single trajectory per user is available. \nWe model the underlying joint distribution through an exponential family. This reduces the task of unit-level counterfactual inference to simultaneously learning a collection of distributions of a given exponential family with different unknown parameters with single observation per distribution. We discuss a computationally efficient method for learning all of these parameters with estimation error scaling linearly with the metric entropy of the space of unknown parameters – if the parameters are an s-sparse linear combination of k known vectors in p dimension\, the error scales as O(s log k/p).  En route\, we derive sufficient conditions for compactly supported distributions to satisfy the logarithmic Sobolev inequality. \nBased on a joint work with Raaz Dwivedi\, Abhin Shah and Greg Wornell (all at MIT) with manuscript available here: https://arxiv.org/abs/2211.08209\n\n\n12:00 – 2:00 pm\nLunch  \n\n\n2:00 – 2:50 pm\nLester Mackey  (Microsoft Research New England) \nTitle: Advances in Distribution Compression \nAbstract: This talk will introduce two new tools for summarizing a probability distribution more effectively than independent sampling or standard Markov chain Monte Carlo thinning:\n1. Given an initial n-point summary (for example\, from independent sampling or a Markov chain)\, kernel thinning finds a subset of only square-root n-points with comparable worst-case integration error across a reproducing kernel Hilbert space.\n2. If the initial summary suffers from biases due to off-target sampling\, tempering\, or burn-in\, Stein thinning simultaneously compresses the summary and improves the accuracy by correcting for these biases.\nThese tools are especially well-suited for tasks that incur substantial downstream computation costs per summary point like organ and tissue modeling in which each simulation consumes 1000s of CPU hours.\nBased on joint work with Raaz Dwivedi\, Marina Riabiz\, Wilson Ye Chen\, Jon Cockayne\, Pawel Swietach\, Steven A. Niederer\, Chris. J. Oates\, Abhishek Shetty\, and Carles Domingo-Enrich.\n\n\n3:00 – 3:30 pm\nCoffee break \n\n\n3:30 – 4:20 pm\nHorng-Tzer Yau (Harvard) \nTitle: On the spectral gap of mean-field spin glass models. \nAbstract: We will discuss recent progress regarding spectral gaps for the Glauber dynamics of spin glasses at high temperature. In addition\, we will also report on estimating the operator norm  of the covariance matrix for the SK model.\n\n\n\n  \nModerators: Benjamin McKenna\, Harvard CMSA & Changji Xu\, Harvard CMSA \n\n  \n \nCMSA COVID-19 Policies
URL:https://cmsa.fas.harvard.edu/event/gramsia2023/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/GRAMSIAcover-600x338-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230831T090000
DTEND;TZID=America/New_York:20230901T170000
DTSTAMP:20260716T055601
CREATED:20230904T063654Z
LAST-MODIFIED:20251026T043812Z
UID:10000820-1693472400-1693587600@cmsa.fas.harvard.edu
SUMMARY:Big Data Conference 2023
DESCRIPTION:On August 31-Sep 1\, 2023 the CMSA hosted the ninth annual Conference on Big Data. The Big Data Conference features speakers from the Harvard community as well as scholars from across the globe\, with talks focusing on computer science\, statistics\, math and physics\, and economics. \nSpeakers: \n\nJacob Andreas\, MIT\nMorgane Austern\, Harvard\nAlbert-László Barabási\, Northeastern\nRachel Cummings\, Columbia\nMelissa Dell\, Harvard\nJianqing Fan\, Princeton\nTommi Jaakkola\, MIT\nAnkur Moitra\, MIT\nMark Sellke\, Harvard\nMarinka Zitnik\, Harvard Medical School\n\nOrganizers: \n\nMichael Douglas\, CMSA\, Harvard University\nYannai Gonczarowski\, Economics and Computer Science\, Harvard University\nLucas Janson\, Statistics and Computer Science\, Harvard University\nTracy Ke\, Statistics\, Harvard University\nHorng-Tzer Yau\, Mathematics and CMSA\, Harvard University\nYue Lu\, Electrical Engineering and Applied Mathematics\, Harvard University\n\nSchedule\n(PDF download) \nThursday\, August 31\, 2023 \n\n\n\n9:00 AM\nBreakfast\n\n\n9:30 AM\nIntroductions\n\n\n9:45–10:45 AM\nAlbert-László Barabási (Northeastern\, Harvard) \nTitle: From Network Medicine to the Foodome: The Dark Matter of Nutrition \nAbstract: A disease is rarely a consequence of an abnormality in a single gene but reflects perturbations to the complex intracellular network. Network medicine offer a platform to explore systematically not only the molecular complexity of a particular disease\, leading to the identification of disease modules and pathways\, but also the molecular relationships between apparently distinct (patho) phenotypes. As an application\, I will explore how we use network medicine to uncover the role individual food molecules in our health. Indeed\, our current understanding of how diet affects our health is limited to the role of 150 key nutritional components systematically tracked by the USDA and other national databases in all foods. Yet\, these nutritional components represent only a tiny fraction of the over 135\,000 distinct\, definable biochemicals present in our food. While many of these biochemicals have documented effects on health\, they remain unquantified in any systematic fashion across different individual foods. Their invisibility to experimental\, clinical\, and epidemiological studies defines them as the ‘Dark Matter of Nutrition.’ I will speak about our efforts to develop a high-resolution library of this nutritional dark matter\, and efforts to understand the role of these molecules on health\, opening novel avenues by which to understand\, avoid\, and control disease. \nhttps://youtu.be/UmgzUwi6K3E\n\n\n10:45–11:00 AM\nBreak\n\n\n11:00 AM–12:00 PM\nRachel Cummings (Columbia) \nTitle: Differentially Private Algorithms for Statistical Estimation Problems \nAbstract: Differential privacy (DP) is widely regarded as a gold standard for privacy-preserving computation over users’ data.  It is a parameterized notion of database privacy that gives a rigorous worst-case bound on the information that can be learned about any one individual from the result of a data analysis task. Algorithmically it is achieved by injecting carefully calibrated randomness into the analysis to balance privacy protections with accuracy of the results.\nIn this talk\, we will survey recent developments in the development of DP algorithms for three important statistical problems\, namely online learning with bandit feedback\, causal interference\, and learning from imbalanced data. For the first problem\, we will show that Thompson sampling — a standard bandit algorithm developed in the 1930s — already satisfies DP due to the inherent randomness of the algorithm. For the second problem of causal inference and counterfactual estimation\, we develop the first DP algorithms for synthetic control\, which has been used non-privately for this task for decades. Finally\, for the problem of imbalanced learning\, where one class is severely underrepresented in the training data\, we show that combining existing techniques such as minority oversampling perform very poorly when applied as pre-processing before a DP learning algorithm; instead we propose novel approaches for privately generating synthetic minority points. \nBased on joint works with Marco Avella Medina\, Vishal Misra\, Yuliia Lut\, Tingting Ou\, Saeyoung Rho\, and Ethan Turok. \nhttps://youtu.be/0cPE6rb1Roo\n\n\n12:00–1:30 PM\nLunch\n\n\n1:30–2:30 PM\nMorgane Austern (Harvard) \nTitle: To split or not to split that is the question: From cross validation to debiased machine learning \nAbstract: Data splitting is a ubiquitous method in statistics with examples ranging from cross-validation to cross-fitting. However\, despite its prevalence\, theoretical guidance regarding its use is still lacking. In this talk\, we will explore two examples and establish an asymptotic theory for it. In the first part of this talk\, we study the cross-validation method\, a ubiquitous method for risk estimation\, and establish its asymptotic properties for a large class of models and with an arbitrary number of folds. Under stability conditions\, we establish a central limit theorem and Berry-Esseen bounds for the cross-validated risk\, which enable us to compute asymptotically accurate confidence intervals. Using our results\, we study the statistical speed-up offered by cross-validation compared to a train-test split procedure. We reveal some surprising behavior of the cross-validated risk and establish the statistically optimal choice for the number of folds. In the second part of this talk\, we study the role of cross-fitting in the generalized method of moments with moments that also depend on some auxiliary functions. Recent lines of work show how one can use generic machine learning estimators for these auxiliary problems\, while maintaining asymptotic normality and root-n consistency of the target parameter of interest. The literature typically requires that these auxiliary problems are fitted on a separate sample or in a cross-fitting manner. We show that when these auxiliary estimation algorithms satisfy natural leave-one-out stability properties\, then sample splitting is not required. This allows for sample reuse\, which can be beneficial in moderately sized sample regimes. \nhttps://youtu.be/L_pHxgoQSgU\n\n\n2:30–2:45 PM\nBreak\n\n\n2:45–3:45 PM\nAnkur Moitra (MIT) \nTitle: Learning from Dynamics \nAbstract: Linear dynamical systems are the canonical model for time series data. They have wide-ranging applications and there is a vast literature on learning their parameters from input-output sequences. Moreover they have received renewed interest because of their connections to recurrent neural networks.\nBut there are wide gaps in our understanding. Existing works have only asymptotic guarantees or else make restrictive assumptions\, e.g. that preclude having any long-range correlations. In this work\, we give a new algorithm based on the method of moments that is computationally efficient and works under essentially minimal assumptions. Our work points to several missed connections\, whereby tools from theoretical machine learning including tensor methods\, can be used in non-stationary settings. \nhttps://youtu.be/UmgzUwi6K3E\n\n\n3:45–4:00 PM\nBreak\n\n\n4:00–5:00 PM\nMark Sellke (Harvard) \nTitle: Algorithmic Thresholds for Spherical Spin Glasses \nAbstract: High-dimensional optimization plays a crucial role in modern statistics and machine learning. I will present recent progress on non-convex optimization problems with random objectives\, focusing on the spherical p-spin glass. This model is related to spiked tensor estimation and has been studied in probability and physics for decades. We will see that a natural class of “stable” optimization algorithms gets stuck at an algorithmic threshold related to geometric properties of the landscape. The algorithmic threshold value is efficiently attained via Langevin dynamics or by a second-order ascent method of Subag. Much of this picture extends to other models\, such as random constraint satisfaction problems at high clause density. \nhttps://youtu.be/JoghiwiIbT8\n\n\n6:00 – 8:00 PM\nBanquet for organizers and speakers\n\n\n\n  \nFriday\, September 1\, 2023 \n\n\n\n9:00 AM\nBreakfast\n\n\n9:30 AM\nIntroductions\n\n\n9:45–10:45 AM\nJacob Andreas (MIT) \nTitle: What Learning Algorithm is In-Context Learning? \nAbstract: Neural sequence models\, especially transformers\, exhibit a remarkable capacity for “in-context” learning. They can construct new predictors from sequences of labeled examples (x\,f(x)) presented in the input without further parameter updates. I’ll present recent findings suggesting that transformer-based in-context learners implement standard learning algorithms implicitly\, by encoding smaller models in their activations\, and updating these implicit models as new examples appear in the context\, using in-context linear regression as a model problem. First\, I’ll show by construction that transformers can implement learning algorithms for linear models based on gradient descent and closed-form ridge regression. Second\, I’ll show that trained in-context learners closely match the predictors computed by gradient descent\, ridge regression\, and exact least-squares regression\, transitioning between different predictors as transformer depth and dataset noise vary\, and converging to Bayesian estimators for large widths and depths. Finally\, we present preliminary evidence that in-context learners share algorithmic features with these predictors: learners’ late layers non-linearly encode weight vectors and moment matrices. These results suggest that in-context learning is understandable in algorithmic terms\, and that (at least in the linear case) learners may rediscover standard estimation algorithms. This work is joint with Ekin Akyürek at MIT\, and Dale Schuurmans\, Tengyu Ma and Denny Zhou at Stanford. \nhttps://youtu.be/UNVl64G3BzA\n\n\n10:45–11:00 AM\nBreak\n\n\n11:00 AM–12:00 PM\nTommi Jaakkola (MIT) \nTitle: Generative modeling and physical processes \nAbstract: Rapidly advancing deep distributional modeling techniques offer a number of opportunities for complex generative tasks\, from natural sciences such as molecules and materials to engineering. I will discuss generative approaches inspired from physical processes including diffusion models and more recent electrostatic models (Poisson flow)\, and how they relate to each other in terms of embedding dimension. From the point of view of applications\, I will highlight our recent work on SE(3) invariant distributional modeling over backbone 3D structures with ability to generate designable monomers without relying on pre-trained protein structure prediction methods as well as state of the art image generation capabilities (Poisson flow). Time permitting\, I will also discuss recent analysis of efficiency of sample generation in such models. \nhttps://youtu.be/GLEwQAWQ85E\n\n\n12:00–1:30 PM\nLunch\n\n\n1:30–2:30 PM\nMarinka Zitnik (Harvard Medical School) \nTitle: Multimodal Learning on Graphs \nAbstract: Understanding biological and natural systems requires modeling data with underlying geometric relationships across scales and modalities such as biological sequences\, chemical constraints\, and graphs of 3D spatial or biological interactions. I will discuss unique challenges for learning from multimodal datasets that are due to varying inductive biases across modalities and the potential absence of explicit graphs in the input. I will describe a framework for structure-inducing pretraining that allows for a comprehensive study of how relational structure can be induced in pretrained language models. We use the framework to explore new graph pretraining objectives that impose relational structure in the induced latent spaces—i.e.\, pretraining objectives that explicitly impose structural constraints on the distance or geometry of pretrained models. Applications in genomic medicine and therapeutic science will be discussed. These include TxGNN\, an AI model enabling zero-shot prediction of therapeutic use across over 17\,000 diseases\, and PINNACLE\, a contextual graph AI model dynamically adjusting its outputs to contexts in which it operates. PINNACLE enhances 3D protein structure representations and predicts the effects of drugs at single-cell resolution. \nhttps://youtu.be/hjt4nsN_8iM\n\n\n2:30–2:45 PM\nBreak\n\n\n2:45–3:45 PM\nJianqing Fan (Princeton) \nTitle: UTOPIA: Universally Trainable Optimal Prediction Intervals Aggregation \nAbstract: Uncertainty quantification for prediction is an intriguing problem with significant applications in various fields\, such as biomedical science\, economic studies\, and weather forecasts. Numerous methods are available for constructing prediction intervals\, such as quantile regression and conformal predictions\, among others. Nevertheless\, model misspecification (especially in high-dimension) or sub-optimal constructions can frequently result in biased or unnecessarily-wide prediction intervals. In this work\, we propose a novel and widely applicable technique for aggregating multiple prediction intervals to minimize the average width of the prediction band along with coverage guarantee\, called Universally Trainable Optimal Predictive Intervals Aggregation (UTOPIA). The method also allows us to directly construct predictive bands based on elementary basis functions.  Our approach is based on linear or convex programming which is easy to implement. All of our proposed methodologies are supported by theoretical guarantees on the coverage probability and optimal average length\, which are detailed in this paper. The effectiveness of our approach is convincingly demonstrated by applying it to synthetic data and two real datasets on finance and macroeconomics. (Joint work Jiawei Ge and Debarghya Mukherjee). \nhttps://youtu.be/WY6dr1oEOrk\n\n\n3:45–4:00 PM\nBreak\n\n\n4:00–5:00 PM\nMelissa Dell (Harvard) \nTitle: Efficient OCR for Building a Diverse Digital History \nAbstract: Many users consult digital archives daily\, but the information they can access is unrepresentative of the diversity of documentary history. The sequence-to-sequence architecture typically used for optical character recognition (OCR) – which jointly learns a vision and language model – is poorly extensible to low-resource document collections\, as learning a language-vision model requires extensive labeled sequences and compute. This study models OCR as a character-level image retrieval problem\, using a contrastively trained vision encoder. Because the model only learns characters’ visual features\, it is more sample-efficient and extensible than existing architectures\, enabling accurate OCR in settings where existing solutions fail. Crucially\, it opens new avenues for community engagement in making digital history more representative of documentary history. \nhttps://youtu.be/u0JY9vURUAs\n\n\n\n  \n\nInformation about the 2022 Big Data Conference can be found here.
URL:https://cmsa.fas.harvard.edu/event/bigdata_2023/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Big Data Conference,Conference,Event
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Big-Data-2023_letter-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230922T160000
DTEND;TZID=America/New_York:20230922T180000
DTSTAMP:20260716T055601
CREATED:20230904T063853Z
LAST-MODIFIED:20240710T192912Z
UID:10001124-1695398400-1695405600@cmsa.fas.harvard.edu
SUMMARY:CMSA/Math Fall Gathering
DESCRIPTION:Friday\, Sep 22\, 2023\n\n4:00 pm\n\nAll CMSA and Math affiliates are invited.
URL:https://cmsa.fas.harvard.edu/event/fallgathering2023/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20231027
DTEND;VALUE=DATE:20231029
DTSTAMP:20260716T055601
CREATED:20230904T060021Z
LAST-MODIFIED:20240624T182341Z
UID:10000002-1698364800-1698537599@cmsa.fas.harvard.edu
SUMMARY:Mathematics in Science: Perspectives and Prospects
DESCRIPTION:Mathematics in Science: Perspectives and Prospects\nA showcase of mathematics in interaction with physics\, computer science\, biology\, and beyond. \nOctober 27–28\, 2023 \nLocation: Harvard University Science Center Hall D & via Zoom. \nDirections and Recommended Lodging \nMathematics in Science: Perspectives and Prospects Youtube Playlist \n  \n\nSpeakers \n\nNima Arkani-Hamed (IAS)\nConstantinos Daskalakis (MIT)\nAlison Etheridge (Oxford)\nMike Freedman (Harvard CMSA)\nGreg Moore (Rutgers)\nBernd Sturmfels (MPI Leipzig)\n\n\nOrganizers \n\nMichael R. Douglas (Harvard CMSA)\nDan Freed (Harvard Math & CMSA)\nMike Hopkins (Harvard Math)\nCumrun Vafa (Harvard Physics)\nHorng-Tzer Yau (Harvard Math)\n\nSchedule\nFriday\, October 27\, 2023 \n\n\n\n2:00–3:15 pm\n\nGreg Moore (Rutgers) \nTitle: Remarks on Physical Mathematics \nAbstract: I will describe some examples of the vigorous modern dialogue between mathematics and theoretical physics (especially high energy and condensed matter physics). I will begin by recalling Stokes’ phenomenon and explain how it is related to some notable developments in quantum field theory from the past 30 years. Time permitting\, I might also say something about the dialogue between mathematicians working on the differential topology of four-manifolds and physicists working on supersymmetric quantum field theories. But I haven’t finished writing the talk yet\, so I don’t know how it will end any more than you do. \nSlides (PDF) \n \n\n\n\n3:15–3:45 pm\nBreak\n\n\n3:45–5:00 pm\n\nBernd Sturmfels (MPI Leipzig) \nTitle: Algebraic Varieties in Quantum Chemistry \nAbstract: We discuss the algebraic geometry behind coupled cluster (CC) theory of quantum many-body systems. The high-dimensional eigenvalue problems that encode the electronic Schroedinger equation are approximated by a hierarchy of polynomial systems at various levels of truncation. The exponential parametrization of the eigenstates gives rise to truncation varieties. These generalize Grassmannians in their Pluecker embedding. We explain how to derive Hamiltonians\, we offer a detailed study of truncation varieties and their CC degrees\, and we present the state of the art in solving the CC equations. This is joint work with Fabian Faulstich and Svala Sverrisdóttir. \nSlides (PDF) \n \n\n\n\n\n  \nSaturday\, October 28\, 2023 \n\n\n\n9:00 am\nBreakfast\n\n\n9:30–10:45 am\n\nMike Freedman (Harvard CMSA) \nTitle: ML\, QML\, and Dynamics: What mathematics can help us understand and advance machine learning? \nAbstract: Vannila deep neural nets DNN repeatedly stretch and fold. They are reminiscent of the logistic map and the Smale horseshoe.  What kind of dynamics is responsible for their expressivity and trainability. Is chaos playing a role? Is the Kolmogorov Arnold representation theorem relevant? Large language models are full of linear maps. Might we look for emergent tensor structures in these highly trained maps in analogy with emergent tensor structures at local minima of certain loss functions in high-energy physics. \nSlides (PDF) \n \n\n\n\n10:45–11:15 am\nBreak\n\n\n11:15 am–12:30 pmvia Zoom\n\nNima Arkani-Hamed (IAS) \nTitle: All-Loop Scattering as A Counting Problem \nAbstract: I will describe a new understanding of scattering amplitudes based on fundamentally combinatorial ideas in the kinematic space of the scattering data. I first discuss a toy model\, the simplest theory of colored scalar particles with cubic interactions\, at all loop orders and to all orders in the topological ‘t Hooft expansion. I will present a novel formula for loop-integrated amplitudes\, with no trace of the conventional sum over Feynman diagrams\, but instead determined by a beautifully simple counting problem attached to any order of the topological expansion. A surprisingly simple shift of kinematic variables converts this apparent toy model into the realistic physics of pions and Yang-Mills theory. These results represent a significant step forward in the decade-long quest to formulate the fundamental physics of the real world in a new language\, where the rules of spacetime and quantum mechanics\, as reflected in the principles of locality and unitarity\, are seen to emerge from deeper mathematical structures. \n \n\n\n\n12:30–2:00 pm\nLunch break\n\n\n2:00–3:15 pm\n\nConstantinos Daskalakis (MIT) \nTitle: How to train deep neural nets to think strategically \nAbstract: Many outstanding challenges in Deep Learning lie at its interface with Game Theory: from playing difficult games like Go to robustifying classifiers against adversarial attacks\, training deep generative models\, and training DNN-based models to interact with each other and with humans. In these applications\, the utilities that the agents aim to optimize are non-concave in the parameters of the underlying DNNs; as a result\, Nash equilibria fail to exist\, and standard equilibrium analysis is inapplicable. So how can one train DNNs to be strategic? What is even the goal of the training? We shed light on these challenges through a combination of learning-theoretic\, complexity-theoretic\, game-theoretic and topological techniques\, presenting obstacles and opportunities for Deep Learning and Game Theory going forward. \nSlides (PDF) \n \n\n\n\n3:15–3:45 pm\nBreak\n\n\n3:45–5:00 pm\n\nAlison Etheridge (Oxford) \nTitle: Modelling hybrid zones \nAbstract: Mathematical models play a fundamental role in theoretical population genetics and\, in turn\, population genetics provides a wealth of mathematical challenges. In this lecture we investigate the interplay between a particular (ubiquitous) form of natural selection\, spatial structure\, and\, if time permits\, so-called genetic drift. A simple mathematical caricature will uncover the importance of the shape of the domain inhabited by a species for the effectiveness of natural selection. \nSlides (PDF) \n \n\n\n\n\nLimited funding to help defray travel expenses is available for graduate students and recent PhDs. If you are a graduate student or postdoc and would like to apply for support\, please register above and send an email to mathsci2023@cmsa.fas.harvard.edu no later than October 9\, 2023. \nPlease include your name\, address\, current status\, university affiliation\, citizenship\, and area of study. F1 visa holders are eligible to apply for support. If you are a graduate student\, please send a brief letter of recommendation from a faculty member to explain the relevance of the conference to your studies or research. If you are a postdoc\, please include a copy of your CV. \n\n 
URL:https://cmsa.fas.harvard.edu/event/mathematics-in-science/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Conference,Event
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/MathScience2023Poster_8.5x11.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231120T090000
DTEND;TZID=America/New_York:20231120T103000
DTSTAMP:20260716T055601
CREATED:20240108T175825Z
LAST-MODIFIED:20240222T055339Z
UID:10001130-1700470800-1700476200@cmsa.fas.harvard.edu
SUMMARY:CMSA/Tsinghua Math-Science Literature Lecture: Scott Kominers
DESCRIPTION:CMSA/Tsinghua Math-Science Literature Lecture \n \nProf. Scott Kominers will present a lecture in the CMSA/Tsinghua Math-Science Literature Lecture Series. \nDate: Monday\, November 20\, 2023 \nTime: 9:00 – 10:30 am ET \nLocation: Via Zoom Webinar \nTitle: 60 Years of Matching: From Gale and Shapley to Trading Networks \nAbstract: Gale and Shapley’s 1962 American Mathematical Monthly paper\, “College Admissions and the Stability of Marriage\,” is by now one of the most cited articles in the journal’s history\, having served as the foundation for an entire branch of the field of market design. This success owes in large part to the beautiful\, applicable\, and surprisingly general theory of matching mechanisms uncovered in Gale and Shapley’s work. This talk traces the history and evolution of matching theory from that paper forward to the present day\, along the way touching on real-world applications to everything from medical residency matching to electricity markets. \nModerator: Sergiy Verstyuk \n\nBeginning in Spring 2020\, the CMSA began hosting a lecture series on literature in the mathematical sciences\, with a focus on significant developments in mathematics that have influenced the discipline\, and the lifetime accomplishments of significant scholars. \n  \nCMSA COVID-19 Policies
URL:https://cmsa.fas.harvard.edu/event/mathscilit2023/
LOCATION:Virtual
CATEGORIES:Event,Math Science Literature Lecture Series
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Mathlit_Kominers_8.5x11.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240126T160000
DTEND;TZID=America/New_York:20240126T180000
DTSTAMP:20260716T055601
CREATED:20240103T210013Z
LAST-MODIFIED:20240222T054337Z
UID:10001109-1706284800-1706292000@cmsa.fas.harvard.edu
SUMMARY:CMSA/MATH Bi-Annual Gathering
DESCRIPTION:On Friday\, Jan. 26\, 2024 the CMSA will host the CMSA/MATH Bi-Annual Gathering for Harvard CMSA and Math affiliates in the CMSA Common Room at 20 Garden Street\, Cambridge MA 02138.
URL:https://cmsa.fas.harvard.edu/event/cmsa-math_2924/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240205T090000
DTEND;TZID=America/New_York:20240329T170000
DTSTAMP:20260716T055601
CREATED:20240103T173754Z
LAST-MODIFIED:20240624T182151Z
UID:10001104-1707123600-1711731600@cmsa.fas.harvard.edu
SUMMARY:Arithmetic Quantum Field Theory Program
DESCRIPTION:Arithmetic Quantum Field Theory Program\nDates: Feb. 5–Mar. 29\, 2024 \nLocation: Harvard CMSA\, 20 Garden Street\, Cambridge MA 02138 \nArithmetic Quantum Field Theory Program Youtube Playlist \nOrganizers: \n\nDavid Ben-Zvi (University of Texas Austin)\nSolomon Friedberg (Boston College)\nNatalie Paquette (University of Washington Seattle)\nBrian Williams (Boston University)\n\nThis program features a weekly seminar series\, workshops\, and a conference. \nThe object of the program is to develop and disseminate exciting new connections emerging between quantum field theory and algebraic number theory\, and in particular between the fundamental invariants of each: partition functions and L-functions. \nOn one hand\, there has been tremendous progress in the past decade in our understanding of the algebraic structures underlying quantum field theory as expressed in terms of the geometry and topology of low-dimensional manifolds\, both on the level of states (via the Atiyah-Segal / Baez-Dolan / Lurie formalism of extended\, functorial field theory) and on the level of observables (via the Beilinson–Drinfeld / Costello–Gwilliam formalism of factorization algebras). On the other hand\, Weil’s Rosetta Stone and the Mazur–Morishita–Kapranov–Reznikov arithmetic topology (the “knots and primes” dictionary) provide a sturdy bridge between the topology of 2- and 3-manifolds and the arithmetic of number fields. Thus\, one can now port over quantum field theoretic ideas to number theory\, as first proposed by Minhyong Kim with his arithmetic counterpart of Chern-Simons theory. Most recently\, the work of Ben-Zvi–Sakellaridis–Venkatesh applies an understanding of the Langlands program as an arithmetic avatar of electric-magnetic duality in four-dimensional gauge theory to reveal a hidden quantum mechanical nature of the theory of $L$-functions. \nThe program will bring together a wide range of mathematicians and physicists working on adjacent areas to explore the emerging notion of arithmetic quantum field theory as a tool to bring quantum physics to bear on questions of interest for the theory of automorphic forms\, harmonic analysis and L-functions. Conversely\, we will explore potential geometric and physical consequences of arithmetic ideas\, for example\, the Langlands correspondence theory of L-functions for 3-manifolds. \n\nSchedule \nThe first week of the program will feature several lecture series aimed at a broad local community of mathematicians and physicists\, aiming to introduce the main ideas underlying our program and help establish a common reference point. \nThe program will host a weekly seminar series on Fridays. \nThe speakers will be selected with the aim of covering a wide panorama of the subjects over the course of the program. \nThe program will conclude with a week-long Conference on Arithmetic Quantum Field Theory March 25–29\, 2024. \n\nAQFT Youtube Playlist \nLecture series \nAll lectures take place in Room G10\, Harvard CMSA\, 20 Garden Street Cambridge. \nWeek 1: Feb. 5–9\, 2024 \nAbstract: In this lecture series we will introduce some of the themes underlying the CMSA program on Arithmetic Quantum Field Theory taking place this winter and the upcoming conference March 25-29\, 2024. \nSome of the themes we plan to discuss include: \nStructures in QFT (like factorization for observables and functorial QFT for states and their relation to geometric / deformation quantization) that are sufficiently algebraic and formal to allow for arithmetic analogs. \nThe setup of arithmetic topology as a bridge between the background of QFT to that of arithmetic (both “global” and “local”)\, including the “middle realm” of positive characteristic function fields. \nQuestions and structures in arithmetic that have been / might be amenable to inspiration from QFT\, in particular the theory of L-functions and the Langlands program. \nSchedule \n\n\n\nMonday\, Feb. 5\, 2024\n \n \n\n\n11:00 am – 12:00 pm\n Minhyong Kim\nArithmetic topology and field theory\nVideo\n(Slides part 1 pdf)\n\n\n1:30 – 2:30 pm\nBrian Williams\nAlgebraic quantum field theory\nVideo\n(Lecture Notes)\n\n\n2:30 – 3:30 pm\nDavid Ben-Zvi\nThe Langlands program via arithmetic QFT\nVideo\n\n\nWednesday\, Feb. 7\, 2024\n \n \n\n\n11:00 am – 12:00 pm\nMinhyong Kim\nArithmetic topology and field theory\nVideo\n(Slides part 2 pdf)\n\n\n2:30 – 3:30 pm\nBrian Williams\nAlgebraic quantum field theory\nVideo\n(Lecture Notes)\n\n\nThursday\, Feb.8\, 2024\n \n \n\n\n2:30 – 3:30 pm\nMinhyong Kim\nArithmetic topology and field theory\nVideo\n(Slides part 3 pdf)\n\n\n4:00 – 5:00 pm\nDavid Ben-Zvi\nThe Langlands program via arithmetic QFT\nVideo\n\n\nFriday\, Feb. 9\, 2024\n \n \n\n\n1:00 – 2:00 pm\nBrian Williams\nAlgebraic quantum field theory\nVideo\n(Lecture Notes)\n\n\n2:00 – 3:00 pm\nDavid Ben-Zvi\nThe Langlands program via arithmetic QFT 1\nVideo\n\n\n3:30 – 4:30 pm\nDavid Ben-Zvi\nThe Langlands program via arithmetic QFT 2\nVideo\n\n\nMonday\, Feb. 26\, 2024\n\n\n\n\n1:00 – 2:00 pm\nOmer Offen (Brandeis)\nPeriod integrals of automorphic forms and the residue method\nVideo\n\n\nTuesday\, Feb. 27\, 2024\n\n\n\n\n2:00 – 3:00 pm\nWei Zhang (MIT)\nShtuka special cycles and their generating series\nVideo\n\n\nFriday\, March 1\, 2024\n\n\n\n\n11:00 am – 12:00 pm\nChen Wan (Rutgers Newark)\nSome examples of the relative Langlands duality\nVideo\n\n\n2:00 – 3:00 pm\nPeng Shan (Tsinghua)\nSkein algebras and quantized Coulomb branches\nVideo\n\n\nThursday\, March 7\, 2024\n\n\n\n\n1:30 – 2:30 pm\nAn Huang (Brandeis)\nTate’s thesis and p-adic strings\nVideo\n\n\n3:00 – 4:00 pm\nJohn Francis (Northwestern)\nIntegrating braided categories over 3-manifolds\nVideo\n\n\nFriday\, March 8\, 2024\n\n\n\n\n1:00 – 2:00 pm\nDihua Jiang (U Minnesota)\nShalika Periods: Functoriality and Arithmetic\nVideo\n\n\nFriday\, March 15\, 2024\n\n\n\n\n11:45 – 1:00 pm\nBaiying Liu (Purdue)\nRecent progress on certain problems related to local Arthur packets of classical groups\nVideo\n\n\n2:15 – 3:30 pm\nTasho Kaletha (Michigan)\nCovers of reductive groups and functoriality\nVideo\n\n\nMonday\, March 18\, 2024\n\n\n\n\n1:00 – 3:00 pm\nXinwen Zhu (Stanford)\nThe tame categorical local Langlands correspondence\nVideo\n\n\n4:30 – 5:30 pm\nNatalie Paquette (U Washington)\nKoszul duality & twisted holography for asymptotically flat spacetimes\n\n\nWednesday\, March 20\, 2024\n\n\n\n\n11:00 – 12:15 pm\nStephen D. Miller (Rutgers)\nWhat 4-graviton scattering amplitudes had to say about the unitary dual\n\n\nFriday\, March 22\, 2024\n\n\n\n\n1:45 – 3:00 pm\nJayce Getz (Duke)\nThe Poisson summation conjecture and the fiber bundle method\nVideo\n\n\n\n\n\n\n\n\n\nProgram Visitors \n\nMina Aganagic\, University of California\, Berkeley\nAnne-Marie Aubert\, Institut de Mathématiques de Jussieu-Paris Rive Gauche\, March 15-29\nClark Barwick\, University of Edinburgh\, February 19-March 15\nAlexander Braverman\, Perimeter Institute\nAlejandra Castro\, Cambridge University\, March 25-29\nYoungJu Choie\, Pohang University of Science and Technology\, February 12-16; March 22-28\nJohn Francis\, Northwestern University\, March 1-14\nDavid Gaiotto\, Perimeter Institute\, March 25-29\nJayce Getz\, Duke University\, March 18-22\nEzra Getzler\, Northwestern University\, March 11-22\nSam Gunningham\, Montana State University\, February 9-12\nSarah Harrison\, Northeastern University\nDihua Jiang\, University of Minnesota\, February 29-March 9\nTasho Kaletha\, University of Michigan\, March 12-20\nMinhyong Kim\, University of Edinburgh\, February 1-29\nAxel Kleinschmidt\, Max Planck Institute for Gravitational Physics\, Potsdam\, March 18-28\nKim Klinger-Logan\, Kansas State University\, March 25-29\nKobi Kremnitzer\, Oxford University\, March 25-29\n\nBaiying Liu\, Purdue University\, March 13-16\n\n\nSteven Miller\, Rutgers University\n\nGreg Moore\, Rutgers University\, February 5-9\nDavid Nadler\, University of California\, Berkeley\, March 17-30\nBảo Châu Ngô\, University of Chicago\, March 25-29\nGeorge Pappas\, Michigan State University\, March 25-29\nDaniel Persson\, Chalmers Institute of Technology\, March 25-29\nSam Raskin\, Yale University\, March 26-29\nYiannis Sakellaridis\, Johns Hopkins University\, March 18-22\nPeng Shan\, Tsinghua University\, February 12-April 14\nAkshay Venkatesh\, Institute for Advanced Study\nRoberto Volpato\, University of Padova\, February 4-10\nChen Wan\, Rutgers University\, February 29-March 9\nFei Yan\, Brookhaven National Laboratory\, March 18-29\nXinwen Zhu\, Stanford University\n\n  \n 
URL:https://cmsa.fas.harvard.edu/event/aqft2024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Programs
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240207T090000
DTEND;TZID=America/New_York:20240207T103000
DTSTAMP:20260716T055601
CREATED:20240103T172620Z
LAST-MODIFIED:20241212T160057Z
UID:10001103-1707296400-1707301800@cmsa.fas.harvard.edu
SUMMARY:CMSA/Tsinghua Math-Science Literature Lecture: Amie Wilkinson
DESCRIPTION:CMSA/Tsinghua Math-Science Literature Lecture \nProf. Amie Wilkinson gave a lecture in the CMSA/Tsinghua Math-Science Literature Lecture Series. \nDate: Wednesday\, February 7\, 2024 \nTime: 9:00–10:30 am ET \nTitle: Stretching and shrinking: 85 years of the Hopf argument for ergodicity\nAbstract:  The early 20th century witnessed an explosion of activity\, much of it centered at Harvard\, on rigorizing the property of ergodicity first proposed by Boltzmann in his 1898  Ergodic Hypothesis for ideal gases. Earlier\, in the 1880’s\, Henri Poincaré and Felix Klein had also initiated a study of discrete groups of hyperbolic isometries. The geodesics in hyperbolic manifolds were discovered to carry a rich structure\, first investigated from a topological perspective by Emil Artin and Marston Morse.  The time was ripe to investigate geodesics in hyperbolic manifolds from an ergodic theoretic (i.e.\, statistical) perspective\, and indeed Gustav Hedlund proved in 1934 that the geodesic flow for closed hyperbolic surfaces is ergodic.\n\nIn 1939\, Eberhard Hopf published a proof of the ergodicity of geodesic flows for negatively curved surfaces containing a novel method\, now known as the Hopf argument.  The Hopf argument\, a “soft” argument for ergodicity of systems with some hyperbolicity (the “stretching and shrinking” in the title) has since seen wide application in geometry\, representation theory and dynamics.  I will discuss three results relying on the Hopf argument:\n\nTheorem (E. Hopf\, 1939\, D. Anosov\, 1967): In a closed manifold of negative sectional curvatures\, almost every geodesic is directionally equidistributed.\n\nTheorem (G. Mostow\, 1968) Let M and N be closed hyperbolic manifolds of dimension at least 3\, and let f:M->N be a homotopy equivalence.  Then f is homotopic to a unique isometry.\n\nTheorem (R. Mañé\, 1983\, A. Avila- S. Crovisier- A.W.\, 2022) The C^1 generic symplectomorphism of a closed symplectic manifold with positive entropy is ergodic.\n  \n\nBeginning in Spring 2020\, the CMSA began hosting a lecture series on literature in the mathematical sciences\, with a focus on significant developments in mathematics that have influenced the discipline\, and the lifetime accomplishments of significant scholars. \n 
URL:https://cmsa.fas.harvard.edu/event/mathscilit2024_aw/
LOCATION:Virtual
CATEGORIES:Event,Math Science Literature Lecture Series
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Mathlit_Wilkinson_letter.png
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240220T160000
DTEND;TZID=America/New_York:20240220T173000
DTSTAMP:20260716T055601
CREATED:20240301T093539Z
LAST-MODIFIED:20250328T150527Z
UID:10002892-1708444800-1708450200@cmsa.fas.harvard.edu
SUMMARY:Math Science Lectures in Honor of Raoul Bott: Maggie Miller: Fibered ribbon knots vs. major 4D conjectures
DESCRIPTION:Fibered ribbon knots vs. major 4D conjectures \nLocation: Harvard University Science Center Hall A & via Zoom webinar \nDates: Feb 20 & 22\, 2024 \nTime: 4:00-5:30 pm \nMaggie Miller is an assistant professor in the mathematics department at the University of Texas at Austin and a Clay Research Fellow. \nThis is the fourth annual Math Science Lecture Series held in Honor of Raoul Bott. \nTalk topic:  Fibered ribbon knots vs. major 4D conjectures\n  \n \nFeb. 20\, 2024 \nTitle: Fibered ribbon knots and the Poincaré conjecture \nAbstract: A knot is “fibered” if its complement in S^3 is the total space of a bundle over the circle\, and ribbon if it bounds a smooth disk into B^4 with no local maxima with respect to radial height. A theorem of Casson-Gordon from 1983 implies that if a fibered ribbon knot does not bound any fibered disk in B^4\, then the smooth 4D Poincaré conjecture is false. I’ll show that unfortunately (?) many ribbon disks bounded by fibered knots are fibered\, giving some criteria for extending fibrations and discuss how one might search for non-fibered examples. \n  \n \nFeb. 22\, 2024 \nTitle: Fibered knots and the slice-ribbon conjecture \nAbstract: The slice-ribbon conjecture (Fox\, 1962) posits that if a knot bounds any smooth disk into B^4\, it also bounds a ribbon disk. The previously discussed work of Casson-Gordon yields an obstruction to many fibered knots being ribbon\, yielding many interesting potential counterexamples to this conjecture — if any happy to bound a non-ribbon disk. In 2022\, Dai-Kong-Mallick-Park-Stoffregen showed that unfortunately( ?) many of these knots don’t bound a smooth disk into B^4 and thus can’t disprove the conjecture. I’ll show a simple alternate proof that a certain interesting knot (the (2\,1)-cable of the figure eight) isn’t slice and discuss remaining open questions. This talk is joint with Paolo Aceto\, Nickolas Castro\, JungHwan Park\, and Andras Stipsicz. \n  \nTalk Chair: Cliff Taubes (Harvard Mathematics) \nModerator: Freid Tong (Harvard CMSA) \n\nRaoul Bott (9/24/1923 – 12/20/2005) is known for the Bott periodicity theorem\, the Morse–Bott functions\, and the Borel–Bott–Weil theorem.
URL:https://cmsa.fas.harvard.edu/event/mathscibott_2024/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Math Science Lectures in Honor of Raoul Bott,Public Lecture,Special Lectures
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240229T160000
DTEND;TZID=America/New_York:20240229T170000
DTSTAMP:20260716T055602
CREATED:20240103T185919Z
LAST-MODIFIED:20250409T192246Z
UID:10001107-1709222400-1709226000@cmsa.fas.harvard.edu
SUMMARY:Fourth Annual Yip Lecture | Josh Tenenbaum | How to grow a mind from a brain: From guessing and betting to thinking and talking
DESCRIPTION:Josh Tenenbaum gave the Fourth Annual Yip Lecture on February 29\, 2024. \nTitle: How to grow a mind from a brain: From guessing and betting to thinking and talking\nTime: 4:00-5:00 pm ET \nLocation: Harvard Science Center \nThe Yip Lecture takes place thanks to the support of Dr. Shing-Yiu Yip. \n \n\nThe previous Yip Lecture featured Andrew Strominger (Harvard)\, who spoke on Black Holes.
URL:https://cmsa.fas.harvard.edu/event/yip-2024/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Event,Public Lecture,Special Lectures,Yip Lecture Series
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240320T090000
DTEND;TZID=America/New_York:20240320T103000
DTSTAMP:20260716T055602
CREATED:20240105T062652Z
LAST-MODIFIED:20241212T160245Z
UID:10001116-1710925200-1710930600@cmsa.fas.harvard.edu
SUMMARY:CMSA/Tsinghua Math-Science Literature Lecture: Cameron Gordon
DESCRIPTION:CMSA/Tsinghua Math-Science Literature Lecture \nProf. Cameron Gordon presented a lecture in the CMSA/Tsinghua Math-Science Literature Lecture Series. \n \nDate: Wednesday\, March 20\, 2024 \nTime: 9:00–10:30 am ET \nLocation: Room G10\, CMSA\, 20 Garden Street\, Cambridge MA and via Zoom Webinar \nTitle: The Unknotting Number of a Knot \nAbstract: One of the oldest and most natural knot invariants is the unknotting number\, which is the minimum number of times a knot must be allowed to pass through itself in order to unknot it. Although this invariant was discussed by Tait almost 150 years ago\, it is still poorly understood. For instance it is not known if it is algorithmically computable\, and indeed there is an 8-crossing knot whose unknotting number is unknown. Nevertheless\, the many developments in knot theory since Tait have led to some understanding of unknotting number\, for example through its connection with 4-dimensional topology. We will give a historical account of this progress\, and discuss some of the questions that are still open. \n  \n\nBeginning in Spring 2020\, the CMSA began hosting a lecture series on literature in the mathematical sciences\, with a focus on significant developments in mathematics that have influenced the discipline\, and the lifetime accomplishments of significant scholars. \n  \nCMSA COVID-19 Policies
URL:https://cmsa.fas.harvard.edu/event/mathscilit2024_cg/
LOCATION:Hybrid
CATEGORIES:Event,Math Science Literature Lecture Series
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/Mathlit_Gordon_letter.jpg
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240325T090000
DTEND;TZID=America/New_York:20240329T170000
DTSTAMP:20260716T055602
CREATED:20240105T034700Z
LAST-MODIFIED:20240624T182211Z
UID:10001114-1711357200-1711731600@cmsa.fas.harvard.edu
SUMMARY:Arithmetic Quantum Field Theory Conference
DESCRIPTION:Arithmetic Quantum Field Theory Conference \nDates: March 25-29\, 2024 \nLocation: Room G10\, Harvard CMSA\, 20 Garden Street\, Cambridge MA 02138 \nArithmetic Quantum Field Theory Conference Youtube Playlist \nOrganizers: \n\nDavid Ben-Zvi (University of Texas Austin)\nSolomon Friedberg (Boston College)\nNatalie Paquette (University of Washington Seattle)\nBrian Williams (Boston University)\n\nScientific Goals: On one hand\, there has been tremendous progress in the past decade in our understanding of the algebraic structures underlying quantum field theory as expressed in terms of the geometry and topology of low-dimensional manifolds\, both on the level of states (via the formalism of extended\, functorial field theory) and on the level of observables (via the formalism of factorization algebras). On the other hand\, the arithmetic topology (or “knots and primes”) dictionary provides a sturdy bridge between the topology of 2- and 3-manifolds and the arithmetic of number fields. Thus\, one can now port over quantum field theoretic ideas to number theory\, as first proposed by Minhyong Kim with his arithmetic counterpart of Chern-Simons theory. Moreover\, automorphic objects appear in string theory where they play a role in the study of graviton scattering. Most recently\, the work of Kapustin-Witten has been extended towards an understanding of the Langlands program as an arithmetic avatar of electric-magnetic duality in four-dimensional gauge theory to reveal a hidden quantum mechanical nature of the theory of L-functions. \nThe conference will bring together a wide range of mathematicians and physicists working on adjacent areas to explore the emerging notion of arithmetic quantum field theory as a tool to bring quantum physics to bear on questions of interest for the theory of automorphic forms\, representation theory\, harmonic analysis and L-functions. Conversely\, we will explore potential geometric and physical consequences of arithmetic ideas. Our program will also build on the significant interactions between number theorists and physicists arising from the frequent appearance of modular and automorphic forms in partition functions\, scattering amplitudes\, and other quantities of interest in quantum field theory and quantum gravity. \nMonday\, March 25: Connections for Women in Mathematics and Physics\nSpeakers \n\nCharlotte Chan (U Michigan)\nKim Klinger-Logan (Kansas State)\nSarah Harrison (Northeastern)\nMelanie Matchett Wood (Harvard)\nFei Yan (Brookhaven National Lab)\n\nTuesday\, March 26–Friday\, March 29: Arithmetic Quantum Field Theory\nSpeakers \n\nAnne-Marie Aubert (IMJ-PRG)\nRoman Bezrukavnikov (MIT)\nSasha Braverman (Toronto / Perimeter)\nAlejandra Castro (Cambridge)\nYoungJu Choie (POSTECH)\nPavel Etingof (MIT)\nDavide Gaiotto (Perimeter)\nAxel Kleinschmidt (Max Planck Institute for Gravitational Physics)\nKobi Kremnitzer (Oxford)\nSpencer Leslie (Boston College)\nDavid Nadler (Berkeley)\nBảo Châu Ngô (U Chicago)\nGeorge Pappas (Michigan State)\nSam Raskin (Yale)\nPeng Shan (Tsinghua)\nZhiwei Yun (MIT)\n\n\nConference Schedule \nArithmetic Quantum Field Theory Conference \nMarch 25–29\, 2024 \nDownload Program (pdf) \n\nMonday\, March 25\, 2024 – Women in Math and Physics \n\n\n\n\n\n8:30 – 9:00 am \n\n\nBreakfast \n\n\n\n\n9:00 – 10:00 am \n\n\nMelanie Matchett Wood (Harvard) \nTitle: Statistics of Number fields\, function fields\, and 3-manifolds \nAbstract: Motivated by conjectures of Cohen\, Lenstra\, and Martinet on the distribution of class groups of number fields\, we describe the analogous questions of understanding distributions of class groups and fundamental groups of curves over finite fields\, and the distribution of fundamental groups of 3-manifolds. We describe results on these distributions in the cases of curves over finite fields and 3-manifolds\, joint with Liu\, Zureick-Brown\, and Sawin\, and discuss how ideas have passed back and forth between the number field\, curves over finite fields\, and 3-manifold settings. \n\n\n\n\n10:00 – 10:20 am \n\n\nCoffee break \n\n\n\n\n10:20 – 11:20 am \n\n\nCharlotte Chan (U Michigan) \nTitle: Generic character sheaves on parahoric subgroups \nAbstract: Lusztig’s theory of character sheaves for connected reductive groups is one of the most important developments in representation theory in the last few decades. I will give an overview of this theory and explain the need\, from the perspective of the representation theory of p-adic groups\, of a theory of character sheaves on jet schemes. Recently\, R. Bezrukavnikov and I have developed the “generic” part of this desired theory. In the simplest nontrivial case\, this resolves a conjecture of Lusztig and produces perverse sheaves on jet schemes compatible with parahoric Deligne–Lusztig induction. This talk is intended to describe in broad strokes what we know about these generic character sheaves\, especially within the context of the Langlands program. \n\n\n\n\n11:30 – 12:30 pm \n\n\nKim Klinger–Logan (Kansas State) \nTitle: Connections between special values of L-functions and scattering amplitudes \nAbstract: In this talk we will attempt make a connection between zeros and special values of L-functions and scattering amplitudes. The connection is best seen through solutions to differential equations of the form $(\Delta-\lambda)f = S$ on $X=SL(2\,\Z)\SL(2\,\R)/SO(2\,\R)$ for $\Delta=y^2(\partial_x^2+\partial_y^2)$ and $H^{-\infty}(X)\cup M$ where $M$ is the space of moderate growth functions. Recently\, Bombieri and Garrett (following work of Hass\, Hejhal\, and Colin de Verdiere) laid out the possibly connection with eigenvalue solutions to equations of this form with zeros of L-functions. On the other hand\, physicists such as Green\, Russo\, Vanhove found that eigenfunction solutions to equations of this form give coefficients of the 4-graviton scattering amplitude. We will elaborate on these connections and discuss some recent work on finding solutions for such equations. This work is in collaboration with Ksenia Fedosova\, Stephen D. Miller\, Danylo Radchenko and Don Zagier. \nSlides (pdf) \n\n\n\n\n12:30 – 2:15 pm \n\n\nLunch  \n\n\n\n\n2:15 – 3:15 pm \n\n\nFei Yan (Brookhaven National Lab) \nTitle: Topological defects on the lattice \nAbstract: Topological defects\, endowed with a rich mathematical structure\, play important roles in condensed matter physics\, high energy theory and quantum information science. Realization of such defects on the lattice not only has interesting theoretical consequences\, but also opens the pathway to quantum simulation of physical systems. In this talk\, I will discuss lattice realizations of topological defects in simple (1+1)-d systems\, taking the transverse field Ising model and the three-state Potts model as examples. Time permitting\, I will also briefly comment on topological defects in non-equilibrium systems\, such as periodically-driven Floquet systems. \n\n\n\n\n3:15 – 3:30 pm \n\n\nCoffee break \n\n\n\n\n3:30 – 4:30 pm \n\n\nSarah Harrison (Northeastern) \nTitle: Liouville Theory and Weil-Petersson Geometry \nAbstract: Two-dimensional conformal field theory is a powerful tool to understand the geometry of surfaces. Liouville conformal field theory in the classical (large central charge) limit encodes the geometry of the moduli space of Riemann surfaces. I describe an efficient algorithm to compute the Weil–Petersson metric to arbitrary accuracy using Zamolodchikov’s recursion relation for conformal blocks\, focusing on examples of a sphere with four punctures and generalizations to other one-complex-dimensional moduli spaces. Comparison with analytic results for volumes and geodesic lengths finds excellent agreement. In the case of M_{0\,4}\, I discuss numerical results for eigenvalues of the Weil-Petersson Laplacian and connections with random matrix theory. Based on work with K. Coleville\, A. Maloney\, K. Namjou\, and T. Numasawa. \nSlides (pdf) \n\n\n\n\n  \nTuesday\, March 26\, 2024 \n\n\n\n\n9:00 – 9:30 am \n\n\nBreakfast \n\n\n\n\n9:30 – 10:30 am \n  \n\n\nRoman Bezrukavnikov (MIT) \nTitle: From affine Hecke category to invariant distributions \nAbstract: By a result of Ben-Zvi\, Nadler and Preygel the cocenter of the affine Hecke category can be identified with coherent sheaves on the appropriate stack of commuting pairs in the Langlands dual group. In a joint work (in progress) with Ciubotaru\, Kazhdan and Varshavsky we recover the space of unipotent invariant distributions on the p-adic group from that category and develop applications to harmonic analysis\, including endoscopic property of unipotent L-packets. Time permitting\, I will explain how a part of this result can be recovered from a geometric realization of Lusztig’s asymptotic affine Hecke algebra J (joint with Karpov and Krylov)\, and present a conjecture generalizing the story to other depth zero representations; another special case of this generalization appears in a joint work with Varshavsky. \n  \n\n\n\n\n10:30 – 11:00am \n\n\nCoffee break \n\n\n\n\n11:00 – 12:00 pm \n\n\nSasha Braverman (Toronto/Perimeter) \nTitle: Hecke operators for algebraic curves over local non-archimedian fields: a survey of some recent results \nAbstract: The main goal of this talk is to discuss Hecke operators and Hecke eigen-functions for the moduli space of G-bundles on a smooth projective algebraic curve X defined over a local non-archimedian field K (possibly with level structures at finitely many points). The plan is to discuss the following subjects: 1) Definition of Hecke operators and the space on which they act 2) Relation to “classical story” – i.e. eigen-functions of Hecke operators for curves over a finite field. 3) Detailed discussion of the examples when X has genus zero and we consider bundles with trivialization at two points. In this case we’ll discuss the relation to classical representation theory of p-adic groups and two representation theory of Cherednik algebras. Based on joint works with P. Etingof\, D.Kazhdan\, and A. Polishchuk. \n\n\n\n\n12:00 – 12:15 pm \n\n\nGroup photo.  \n\n\n\n\n12:15 – 1:30 pm \n\n\nLunch  \n\n\n\n\n1:30 – 2:30 pm \n\n\nPeng Shan (Tsinghua) \nTitle: Modularity for W-algebras\, affine Springer fibres and associated variety \nAbstract: I will explain a bijection between admissible representations of affine Kac-Moody algebras and fixed points in affine Springer fibres. I will also explain how to match the modular group action on the characters of representations with the one defined by Cherednik in terms of double affine Hecke algebras\, and extensions of these relations to representations of W-algebras. If time permits\, I will discuss some extension of these results to non-admissible levels and some conjectures about their associated varieties. This is based on joint work with Dan Xie\, Wenbin Yan\, and Qixian Zhao. \n\n\n\n\n2:30 – 3:00 pm \n\n\nCoffee break \n\n\n\n\n3:00 – 4:00 pm \n\n\nBảo Châu Ngô (U Chicago) \nTitle: On the nonabelian Fourier kernel and the Lafforgue transform \nAbstract: In the case of SL2\, we present an analytic formula for the nonabelian Fourier kernel responsible for the functional equation of automorphic L-functions. We use the Gelfand-Graev formula for Langlands’ stable transfer factor and a linear map between the Bernstein center and the cocenter that we call the Lafforgue transform. This is a joint work with Zhilin Luo. \n\n\n\n\n  \nWednesday\, March 27\, 2024 \n  \n\n\n\n\n9:00 – 9:30 am \n\n\nBreakfast \n\n\n\n\n9:30 – 10:30 am \n\n\nYoungJu Choie (POSTECH) \nTitle: Schubert Eisenstein series and Poisson summation for Schubert varieties \nAbstract: Schubert Eisenstein series by restricting the summation in a degenerate Eisenstein series to a particular Schubert variety has been studied. In the case of GL3 over Q it was proved that these Schubert Eisenstein series have meromorphic continuations in all parameters and conjectured the same is true in general. We revisit the conjecture and relate it to the program of Braverman\, Kazhdan\, Lafforgue\, Ngˆo\, and Sakellaridis aimed at establishing generalizations of the Poisson summation formula. This is a joint work with Jayce Getz. \nSlides (pdf) \n\n\n\n\n10:30 – 11:00 am \n\n\nCoffee break \n\n\n\n\n11:00 – 12:00 pm \n\n\nAxel Kleinschmidt (MPI) \nTitle: Automorphic representations in string amplitudes \nAbstract: I will review how automorphic representations arise in the low-energy expansion of string scattering amplitudes\, highlighting the connection found by Green/Miller/Vanhove between wavefront sets and BPS conditions. To study the wavefront sets I will present reduction principles for the calculation of Fourier coefficients. String theory also predicts new types of automorphic objects that are characterised by lacking finiteness under the center of the universal enveloping algebra. \nSlides (pdf) \n\n\n\n\n12:00 – 1:30 pm \n\n\nLunch  \n\n\n\n\n1:30 – 2:30 pm \n\n\nPavel Etingof (MIT) \nTitle: Analytic Langlands correspondence over C and R \nAbstract: I will review the analytic component of the geometric Langlands correspondence\, developed recently in my joint work with E. Frenkel and D. Kazhdan (based on previous works by other authors)\, with a special focus on archimedian local fields\, especially R. This is based on our work with E. Frenkel and D. Kazhdan and insights shared by D. Gaiotto and E. Witten. \nSlides (pdf) \n\n\n\n\n2:30 – 3:00 pm \n\n\nCoffee break \n\n\n\n\n3:00 – 4:00 pm \n\n\nDavide Gaiotto (Perimeter) \nTitle: Unexpected Unitarity \nAbstract: Much of the mathematical content of Supersymmetric Quantum Field Theories can be extracted through “twisted theories”: simplified QFTs which are topological (or holomorphic) in a derived sense and often amenable of a rigorous mathematical treatment. The twisting procedure destroys or obfuscates certain properties of the underlying SQFTs\, including unitarity. I will discuss a variety of situations where some form of unitarity can be restored\, endowing the twisted theories with unexpected structures. This includes the recently developed Analytic Langlands program\, an analytic version of Symplectic Duality\, an A-model description of quantization (as opposed to deformation quantization) and other constructions of Hodge-theoretic or twistorial flavour. \n  \n\n\n\n\nThursday\, March 28\, 2024 \n  \n\n\n\n\n8:30 – 9:00 am \n\n\nBreakfast \n\n\n\n\n9:00 – 10:00 am \n\n\nSpencer Leslie (Boston College) \nTitle: Relative Langlands and endoscopy \nAbstract: Spherical varieties play an important role in the study of periods of automorphic forms. But very closely related varieties can lead to very distinct arithmetic problems. Motivated by applications to relative trace formulas\, we discuss the natural question of distinguishing different forms of a given spherical variety in arithmetic settings\, giving a solution for symmetric varieties. It turns out that the answer is intimately connected with the construction of the dual Hamiltonian variety associated with the symmetric variety by Ben-Zvi\, Sakellaridis\, and Venkatesh. I will explain the source of these questions in the theory of endoscopy for symmetric varieties\, with application to the (pre)-stabilization of relative trace formulas. \n\n\n\n\n10:00 – 10:30 am \n\n\nCoffee break \n\n\n\n\n10:30 – 11:30 am \n\n\nAnne-Marie Aubert (IMJ–PRG) \nTitle: The Local Langlands correspondence: from extended quotients to affine Hecke algebras \nAbstract: We will introduce the notion of extended quotient\, illustrate it on examples\, and show how it can be used to construct the local Langlands correspondence in the nonarchimedean case. Next\, we will connect extended quotients\, that are attached to the Bernstein decomposition of the category of smooth representations of p-adic groups\, and their Langlands duals\, to representations of affine Hecke algebras in order to get a description of the LLC as a correspondence between the categories of modules of two collections of such algebras. \nSlides (pdf) \n\n\n\n\n11:45 – 12:45 pm \n\n\nKobi Kremnitzer (Oxford) \nTitle: Functional analysis over the integers\, L-functions and global Hodge theory  \nAbstract: In this talk I will explain how using bornological methods one can develop functional analysis over the integers unifying Archimedean and non-Archimedean analysis. I will give examples of algebras of functions and distributions defined over the integers which base change to the usual algebras over the reals and p-adics. Using these it is possible to write some version of L-functions over the integers. I will then introduce an analytic stack over the integers for which the category of quasi-coherent sheaves gives global Hodge structures. I will relate the integral L-functions to trivialisations of line bundles on this stack. I will also explain how to define a cohomology theory for schemes valued in global Hodge structures (possibly related to q-deRham) and speculate on the relation between the determinant of cohomology and L-functions. This is work in progress joint with Federico Bambozzi and Jack Kelly. \n\n\n\n\n12:45 – 2:00 pm \n\n\nLunch  \n\n\n\n\n2:00 – 3:00 pm \n\n\nDavid Nadler (Berkeley) \nTitle: Going to the boundary \nAbstract: I’ll describe several situations where degenerating a marked smooth curve to a marked nodal curve leads to interesting structures on automorphic moduli spaces. In particular\, I’ll discuss its implications for the cocenter of the affine Hecke category\, real-symmetric duality in relative Langlands\, and some other conjectural situations. The talk will borrow from joint work with various authors including D. Ben-Zvi\, T.-H. Chen\, P. Li\, and Z. Yun. \n\n\n\n\n3:00 – 3:30 pm \n\n\nCoffee break \n\n\n\n\nFriday\, March 29\, 2024 \n  \n\n\n\n\n9:00 – 9:30 am \n\n\nBreakfast \n\n\n\n\n9:30 – 10:30 am \n\n\nGeorge Pappas (Michigan State) \nTitle: Finite and p-adic Chern-Simons type invariants \nAbstract: We will define arithmetic invariants of Galois covers and of ‘etale local systems which are inspired by the classical constructions of Dijkgraaf-Witten and Chern-Simons. We will discuss various conjectures and recent results about these invariants. \n\n\n\n\n10:30 – 11:00 am \n\n\nCoffee break \n\n\n\n\n11:00 – 12:00 pm \n\n\nSam Raskin (Yale) \nTitle: The geometric Langlands conjecture \nAbstract: I will describe the main ideas that go into the proof of the (unramified\, global) geometric Langlands conjecture. All of this work is joint with Gaitsgory and some parts are joint with Arinkin\, Beraldo\, Chen\, Faergeman\, Lin\, and Rozenblyum. \n\n\n\n\n12:00 – 1:30 pm \n\n\nLunch  \n\n\n\n\n1:30 – 2:30 pm \n\n\nAlejandra Castro (Cambridge) \nTitle: The light we can see: Extracting black holes from weak Jacobi forms \nAbstract: Modular forms play a pivotal role in the counting of black hole microstates. The underlying modular symmetry of counting formulae was key in the precise match between the Bekenstein-Hawking entropy of supersymmetric black holes and Cardy’s formula for the asymptotic growth of states. The goal of this talk is to revisit the connection between modular forms and black hole entropy\, and tie it with other consistency conditions of AdS/CFT. We will focus our attention on weak Jacobi forms.  \nI will quantify how constraints on polar states affect the asymptotic growth of non-polar states in weak Jacobi forms. The constraints I’ll consider are sparseness conditions on the Fourier coefficients of these forms\, which are necessary to interpret them as gravitational path integrals. In short\, the constraints will leave an imprint on the subleading corrections to the asymptotic growth of heavy states. With this we will revisit the UV/IR connection that relates black hole microstate counting to modular forms. In particular\, I’ll provide a microscopic interpretation of the logarithmic corrections to the entropy of supersymmetric black holes and tie it to consistency conditions in AdS_3/CFT_2. \n\n\n\n\n2:30 – 3:00 pm \n\n\nCoffee break \n\n\n\n\n3:00 – 4:00 pm \n\n\nZhiwei Yun (MIT) \nTitle: Theta correspondence and relative Langlands \nAbstract: A reductive dual pair (such as a symplectic group and an orthogonal group) acting on the tensor product of their standard representations is an example of hyperspherical varieties\, and is the geometric avatar for theta correspondence. I will explain two geometric results/constructions motivated by the theta correspondence over finite fields. The first one describes how principal series representations behave under theta correspondence using Springer correspondence (joint with Jiajun Ma\, Congling Qiu and Jialiang Zou). The second one is a definition of character sheaves in the setup of theta correspondence (joint with Shamgar Gurevich). I will speculate how the first result fits into relative Langlands duality. \n\n\n\n\n\nLimited funding to help defray travel expenses is available for graduate students and recent PhDs. If you are a graduate student or postdoc and would like to apply for support\, please register above and send an email to cstillman@math.harvard.eduno later than Sunday\, February 25\, 2024. \nPlease include your name\, address\, current status\, university affiliation\, citizenship\, and area of study. F1 visa holders are eligible to apply for support. If you are a graduate student\, please send a brief letter of recommendation from a faculty member to explain the relevance of the conference to your studies or research. If you are a postdoc\, please include a copy of your CV. \n\nThis event will be co-funded by the National Science Foundation.\nThe conference is part of the Arithmetic Quantum Field Theory Program\, Feb 4-March 29\, 2024.
URL:https://cmsa.fas.harvard.edu/event/aqftconf/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Conference
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END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240328T163000
DTEND;TZID=America/New_York:20240328T173000
DTSTAMP:20260716T055602
CREATED:20240103T175709Z
LAST-MODIFIED:20250409T192237Z
UID:10001105-1711643400-1711647000@cmsa.fas.harvard.edu
SUMMARY:2024 Ding Shum Lecture: Yann LeCun: Objective-Driven AI: Towards AI systems that can learn\, remember\, reason\, and plan
DESCRIPTION:LECTURE SLIDES (pdf) \nOn March 28\, 2024\, the CMSA will host the fifth annual Ding Shum Lecture\, given by Yann LeCun. \nTime: 4:30–5:30 pm ET \nSpeaker: Yann Lecun\, New York University & META \nLocation: Harvard Science Center  Hall A & via Zoom Webinar \nTitle: Objective-Driven AI: Towards AI systems that can learn\, remember\, reason\, and plan \n\n\nAbstract:  \nHow could machines learn as efficiently as humans and animals? \nHow could machines learn how the world works and acquire common sense? \nHow could machines learn to reason and plan? \nCurrent AI architectures\, such as Auto-Regressive Large Language Models fall short. I will propose a modular cognitive architecture that may constitute a path towards answering these questions. The centerpiece of the architecture is a predictive world model that allows the system to predict the consequences of its actions and to plan a sequence of actions that optimize a set of objectives. The objectives include guardrails that guarantee the system’s controllability and safety. The world model employs a Hierarchical Joint Embedding Predictive Architecture (H-JEPA) trained with self-supervised learning. The JEPA learns abstract representations of the percepts that are simultaneously maximally informative and maximally predictable. The corresponding working paper is available here: https://openreview.net/forum?id=BZ5a1r-kVsf \n\n\n\n\n\n\n\n\n\n\nThis event is made possible by the generous funding of Ding Lei and Harry Shum. \n 
URL:https://cmsa.fas.harvard.edu/event/2024_dingshum/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Ding Shum Lecture,Event,Public Lecture,Special Lectures
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END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240405T140000
DTEND;TZID=America/New_York:20240406T170000
DTSTAMP:20260716T055602
CREATED:20240105T070812Z
LAST-MODIFIED:20250305T204914Z
UID:10001118-1712325600-1712422800@cmsa.fas.harvard.edu
SUMMARY:Current Developments in Mathematics Conference 2024
DESCRIPTION:CURRENT DEVELOPMENTS IN MATHEMATICS 2024\nAPRIL 5-6\, 2024\nHARVARD UNIVERSITY SCIENCE CENTER\nLECTURE HALL C\nhttps://www.math.harvard.edu/event/current-developments-in-mathematics-2024/\n  \n\nSpeakers:\nDaniel Cristofaro-Gardiner – University of Maryland\nSamit Dasgupta – Duke University\nJiaoyang Huang – University of Pennsylvania\nDaniel Litt – University of Toronto\nLisa Piccirillo – MIT/University of Texas\n\n\n\n\nDownload PDF for a detailed schedule of lectures and events. \n  \n\n\n\n\n\n\n\n\nFriday\, April 5 \n\n\n\n\n\n\n\n\n\n\nSaturday\, April 6 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n1:30 p.m. – 2:20 p.m. Part 1\n2:20 p.m. – 2:30 p.m. Break\n2:30 p.m. – 3:20 p.m. Part 2\n\nJiaoyang Huang \nRandom Matrix Statistics and Airy Line Ensembles \n\n\n\n\n\n\n\n\n\n\n\n9:05 a.m. – 9:55 a.m. Part 1\n9:55 a.m. – 10:05 a.m. Break\n10:05 a.m. – 10:55 a.m. Part 2\n\nDaniel Litt \nMotives\, mapping class groups\, and monodromy \n\n\n\n\n\n\n\n\n\n\n\n\n3:20 p.m. – 3:35 p.m. \nBreak \n\n\n\n\n\n\n\n\n\n\n10:55 a.m. – 11:10 a.m. \nBreak \n\n\n\n\n\n\n\n\n\n\n\n\n\n3:35 p.m. – 4:25 p.m. Part 1\n4:25 p.m. – 4:35 p.m. Break\n4:35 p.m. – 5:25 p.m. Part 2\n\nLisa Piccirillo \nExotic phenomena in dimension 4 \n\n\n\n\n\n\n\n\n\n\n\n11:10 a.m. – 12 p.m. Part 1\n12 p.m. – 1:30 p.m. Lunch\n1:30 p.m. – 2:20 p.m. Part 2\n\nSamit Dasgupta \nStark’s conjectures and explicit class field theory \n\n\n\n\n\n\n\n\n\n\n\n\n\n2:20 p.m. – 2:35 p.m. \nBreak \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n2:35 p.m. – 3:25 p.m. Part 1\n3:25 p.m. – 3:35 p.m. Break\n3:35 p.m. – 4:25 p.m. Part 2\n\nDan Cristofaro-Gardiner \nLow-dimensional topology and dynamics \n\n\n\n\n\n\n\n\n  \n  \nOrganizers: David Jerison\, Paul Seidel\, Nike Sun (MIT); Denis Auroux\, Mark Kisin\, Lauren Williams\, Horng-Tzer Yau\, Shing-Tung Yau (Harvard). \nSponsored by the National Science Foundation\, Harvard University Mathematics\, and the Massachusetts Institute of Technology. \nHarvard University is committed to maintaining a safe and healthy educational and work environment in which no member of the University community is\, on the basis of sex\, sexual orientation\, or gender identity\, excluded from participation in\, denied the benefits of\, or subjected to discrimination in any University program or activity. More information can be found here.
URL:https://cmsa.fas.harvard.edu/event/cdm-2024/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Conference
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END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240415T090000
DTEND;TZID=America/New_York:20240524T170000
DTSTAMP:20260716T055602
CREATED:20230904T173915Z
LAST-MODIFIED:20240624T181936Z
UID:10000003-1713171600-1716570000@cmsa.fas.harvard.edu
SUMMARY:Program on Mathematical Aspects of Scattering Amplitudes
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Program \nDates: April 15 – May 24\, 2024 \nLocation: Harvard CMSA\, 20 Garden Street\, Cambridge\, MA 02138 \nThis program will bring together and foster interaction between theoretical physicists and mathematicians working on various topics connected to recent developments in our understanding of scattering amplitudes in quantum field theory. The field has advanced considerably since 2019 when the CMSA hosted the program “Spacetime and Quantum Mechanics\, Total Positivity and Motives.” Recent developments have primed this area for further significant advances\, which will be facilitated by bringing together many of the relevant experts for intensive discussion and collaboration. \nThe program will feature a weekly seminar series. \nTuesday\, April 16\, 2024\n4:15 pm\nSabrina Pasterski\, Perimeter Institute\nTitle: Radiation in Holography \n[Physics Talk]\nWednesday\, April 17\, 2024\n4:30 pm –  Cruft 309\nAna-Maria Raclariu\, King’s College London \nThursday\, April 18\, 2024\n4:15 pm\nLionel Mason\, University of Oxford\nTitle: Hidden symmetries of SD Poincare Einstein metrics in split signature \n[Physics Talk]\nTuesday\, April 23\, 2024\n4:30 pm – Jefferson 256\nJuan Maldacena\, Institute for Advanced Study \nThursday\, April 25\, 2024\n4:15 pm\nTomasz Taylor\, Northeastern University\nTitle: Progress in Yang-Mills-Liouville Theory \n[CMSA Colloquium]\nMonday\, April 29\, 2024\n4:30 – 5:30 pm\nLance Dixon\, Stanford\nTitle: The DNA of Particle Scattering \nTuesday\, April 30\, 2024\n9:00 am- Jefferson 453\nNima Arkani-Hamed\, IAS\nTitle: Surfaceology and the Real World Part 1 \n1:00 pm – Jefferson 453\nNima Arkani-Hamed\, IAS\nTitle: Surfaceology and the Real World Part 2 \n4:00 pm – Jefferson 453\nNima Arkani-Hamed\, IAS\nTitle: Surfaceology and the Real World Part 3 \nWednesday\, May 1\, 2024\n11:00 am – Science Center 507\nJaroslav Trnka\, UC Davis\nTitle: Loops of loops expansion in the Amplituhedron \n3:00 pm\nYu-tin Huang\, National Taiwan University\nTitle: Loop in trees: Chambers in amplitudes and correlation functions \n4:00 pm\nLivia Ferro\, University of Hertfordshire\nTitle: Scattering Amplitudes from Null-cone Geometry \n5:00 pm\nStephan Stieberger\, Max Planck Institute\nTitle: One-loop Double Copy Relation in String Theory and Twisted (Co)homology \nThursday\, May 2\, 2024\n11:00 am – Science Center 310\nDaniil Rudenko\, Chicago\nTitle: Introduction to Cluster Polylogarithms \nFriday\, May 3\, 2024\n11:00 am\nAndrew McLeod\, Edinburgh\nTitle: Genealogical Constraints on Feynman Integrals \nTuesday\, May 7\, 2024\n3:00 pm\nJacob Bourjaily\, Penn State\nTitle: The Algebraic and Transcendental Structure of Perturbative QFT \nWednesday\, May 8\, 2024\n3:00 pm\nRuth Britto\, Trinity\nTitle: Cuts and Symbols \nTuesday\, May 14\, 2024\n3:00 pm\nJames Drummond\, University of Southampton\nTitle: Multiple light-like Wilson loops in N=4 super Yang-Mills theory \nWednesday\, May 15\, 2024\n3:00 pm\nMatteo Parisi\, Harvard CMSA\nTitle: The amplituhedron and cluster algebras \nTuesday\, May 21\, 2024\n11:00 am\nMichael Borinsky\, ETH Zurich\nTitle: On the Euler characteristic of the commutative graph complex and the top-weight cohomology of the moduli space of curves \nWednesday\, May 22\, 2024\n11:00 am\nChaim Even-Zohar\, Technion\nTitle: Amplituhedron tiles and twistor polynomials \n  \nOrganizers: \n\nNima Arkani-Hamed (Institute for Advanced Study)\nMarcus Spradlin (Brown University)\nAndrew Strominger (Harvard University)\nAnastasia Volovich (Brown University)\nLauren Williams (Harvard University)\n\nParticipants: \n\n\nMichael Borinsky\, ETH Zurich\nJacob Bourjaily\, Pennsylvania State University\nRuth Britto\, Trinity College\nLance Dixon\, Stanford Linear Accelerator Center\nJames Drummond\, University of Southampton\nChaim Even-Zohar\, Technion\nLivia Ferro\, University of Hertfordshire\nCarolina Figueiredo\, Princeton University\nHadleigh Frost\, Oxford University\nBruno Gimenez\, University of Southampton\nOmer Gurdogan\, University of Southampton\nXuhua He\, Chinese University of Hong Kong\nPaul Heslop\, Durham University\nYu-Tin Huang\, National Taiwan University\nDani Kaufman\, University of Copenhagen\nJianrong Li\, University of Vienna\nTomasz Lukowski\, University of Hertfordshire\nYelena Mandelshtam\, University of California\, Berkeley\nLionel Mason\, University of Oxford\nAndrew McLeod\, University of Edinburgh\nNatalie Paquette\, University of Washington\nMatteo Parisi\, Harvard University\nSabrina Pasterski\, Perimeter Institute\nDmitri Pavlov\, Max Planck Institute for Mathematics in the Sciences\, Leipzig\nLizzie Pratt\, University of California\, Berkeley\nClaudia Rella\, University of Geneva\nDaniil Rudenko\, University of Chicago\nGiulio Salvatori\, Max Planck Institute for Physics\nMelissa Sherman-Bennett\, Massachusetts Institute of Technology\nJonah Stalknecht\, University of Hertfordshire\nStephan Stieberger\, Max Planck Institute\nTomasz Taylor\, Northeastern University\nRan Tessler\, Weizmann Institute of Science\nHugh Thomas\, Université du Québec à Montréal\nJaroslav Trnka\, University of California\, Davis\nCristian Vergu\, Pennsylvania State University
URL:https://cmsa.fas.harvard.edu/event/scattering-amplitudes/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Programs
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END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240429T090000
DTEND;TZID=America/New_York:20240503T170000
DTSTAMP:20260716T055602
CREATED:20240105T071054Z
LAST-MODIFIED:20240624T182013Z
UID:10001119-1714381200-1714755600@cmsa.fas.harvard.edu
SUMMARY:Workshop on Global Categorical Symmetries
DESCRIPTION:The CMSA will be hosting a Workshop on Global Categorical Symmetries from April 29–May 3\, 2024. \nParticipation in the workshop is by invitation. \nThe workshop will hold three Symmetry Colloquia open to the community on Thursday\, May 2\, 2024. \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 2:00 – 2:50 pm \nSpeaker: Clay Còrdova\, University of Chicago \nTitle: Particle-Soliton Degeneracies from Spontaneously Broken Non-Invertible Symmetry \nAbstract: We study non-invertible topological symmetry operators in massive quantum field theories in (1+1) dimensions. In phases where this symmetry is spontaneously broken we show that the particle spectrum often has degeneracies dictated by the non-invertible symmetry and we deduce a procedure to determine the allowed multiplets. These degeneracies are robust predictions and do not require integrability or other special features of renormalization group flows. We exhibit these conclusions in examples where the spectrum is known\, recovering soliton and particle degeneracies. For instance\, the Tricritical Ising model deformed by the subleading Z2 odd operator flows to a gapped phase with two degenerate vacua. This flow enjoys a Fibonacci fusion category symmetry which implies a threefold degeneracy of its particle states\, relating the mass of solitons interpolating between vacua and particles supported in a single vacuum. \n  \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 3:00 – 3:50 pm \nSpeaker: Thomas Dumitrescu\, UCLA \nTitle: Symmetries\, Invertible Field Theories\, and Gauge Theory Phases \nAbstract: I will start with a brief overview of gauge theory phases in 3+1 dimensions through the lens of higher symmetries — in particular the realization of 1-form symmetries acting on loop order parameters. I will then review recent progress in refining this characterization using invertible field theories\, or equivalently symmetry protected topological phases (SPTs). This refinement leads to new results in gauge theories with fundamental matter\, such as quantum chromodynamics (QCD)\, which do not possess 1-form symmetries. I will explain why these theories must sometimes undergo a phase transition between their confining and Higgs regimes\, despite the fact that classic results and standard lore say they should be continuously connected. \n  \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 4:30 – 5:20 pm \nSpeaker: Theo Johnson-Freyd\, Dalhousie University and Perimeter Institute \nTitle: The Universal Target Category \nAbstract: Hilbert’s Nullstellensatz says that the complex numbers C satisfy a universal property among all R-algebras: every not-too-large nonzero commutative R-algebra maps to C. Deligne proved a similar statement in categorical dimension 1: every not-too-large symmetric monoidal category over R maps to the category sVec of super vector spaces. In other words\, sVec (and not Vec!) is “algebraically closed”. These statements help explain why quantum field theory requires imaginary numbers and fermions. I will describe the universal symmetric monoidal higher category that extends the sequence C\, sVec\, …. This is joint work in progress with David Reutter\, and builds on closely-related work by GCS collaborators Freed\, Scheimbauer\, and Teleman and Schlank et al. \n  \nOrganizers:\nDan Freed (Harvard CMSA & Math)\nConstantin Teleman  (UC Berkeley) \nThis event is co-sponsored by the Simons Foundation. 
URL:https://cmsa.fas.harvard.edu/event/globalcomputing24/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Symmetry-Lectures-poster-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T140000
DTEND;TZID=America/New_York:20240502T145000
DTSTAMP:20260716T055602
CREATED:20240415T162849Z
LAST-MODIFIED:20240417T181513Z
UID:10003356-1714658400-1714661400@cmsa.fas.harvard.edu
SUMMARY:Symmetry Colloquia - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Clay Còrdova\, University of Chicago \nTitle:  Particle-Soliton Degeneracies from Spontaneously Broken Non-Invertible Symmetry \nAbstract: We study non-invertible topological symmetry operators in massive quantum field theories in (1+1) dimensions. In phases where this symmetry is spontaneously broken we show that the particle spectrum often has degeneracies dictated by the non-invertible symmetry and we deduce a procedure to determine the allowed multiplets. These degeneracies are robust predictions and do not require integrability or other special features of renormalization group flows. We exhibit these conclusions in examples where the spectrum is known\, recovering soliton and particle degeneracies. For instance\, the Tricritical Ising model deformed by the subleading Z2 odd operator flows to a gapped phase with two degenerate vacua. This flow enjoys a Fibonacci fusion category symmetry which implies a threefold degeneracy of its particle states\, relating the mass of solitons interpolating between vacua and particles supported in a single vacuum.
URL:https://cmsa.fas.harvard.edu/event/gcs24_cordova/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Pages-from-2403.08883_2.47.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T150000
DTEND;TZID=America/New_York:20240502T155000
DTSTAMP:20260716T055602
CREATED:20240415T163531Z
LAST-MODIFIED:20240417T181737Z
UID:10003357-1714662000-1714665000@cmsa.fas.harvard.edu
SUMMARY:Symmetry Colloquia  - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Thomas Dumitrescu\, UCLA \nTitle: Symmetries\, Invertible Field Theories\, and Gauge Theory Phases \nAbstract: I will start with a brief overview of gauge theory phases in 3+1 dimensions through the lens of higher symmetries — in particular the realization of 1-form symmetries acting on loop order parameters. I will then review recent progress in refining this characterization using invertible field theories\, or equivalently symmetry protected topological phases (SPTs). This refinement leads to new results in gauge theories with fundamental matter\, such as quantum chromodynamics (QCD)\, which do not possess 1-form symmetries. I will explain why these theories must sometimes undergo a phase transition between their confining and Higgs regimes\, despite the fact that classic results and standard lore say they should be continuously connected.
URL:https://cmsa.fas.harvard.edu/event/gcs24_dumitrescu/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Pages-from-2312.16898_phase-transition.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T163000
DTEND;TZID=America/New_York:20240502T172000
DTSTAMP:20260716T055602
CREATED:20240415T163546Z
LAST-MODIFIED:20240422T153733Z
UID:10003358-1714667400-1714670400@cmsa.fas.harvard.edu
SUMMARY:Symmetry Colloquia  - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Theo Johnson-Freyd\, Dalhousie University and Perimeter Institute \nTitle: The Universal Target Category \nAbstract: Hilbert’s Nullstellensatz says that the complex numbers C satisfy a universal property among all R-algebras: every not-too-large nonzero commutative R-algebra maps to C. Deligne proved a similar statement in categorical dimension 1: every not-too-large symmetric monoidal category over R maps to the category sVec of super vector spaces. In other words\, sVec (and not Vec!) is “algebraically closed”. These statements help explain why quantum field theory requires imaginary numbers and fermions. I will describe the universal symmetric monoidal higher category that extends the sequence C\, sVec\, …. This is joint work in progress with David Reutter\, and builds on closely-related work by GCS collaborators Freed\, Scheimbauer\, and Teleman and Schlank et al.
URL:https://cmsa.fas.harvard.edu/event/gcs24_johnson-freyd/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Pages-from-2105.15167_Johnson-Freyd.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240529T090000
DTEND;TZID=America/New_York:20240531T170000
DTSTAMP:20260716T055602
CREATED:20240105T071351Z
LAST-MODIFIED:20240624T164905Z
UID:10001120-1716973200-1717174800@cmsa.fas.harvard.edu
SUMMARY:Amplituhedra\, Cluster Algebras\, and Positive Geometry
DESCRIPTION:Amplituhedra\, Cluster Algebras\, and Positive Geometry \nDates: May 29-31\, 2024 \nLocation: Harvard CMSA\, 20 Garden Street\, Cambridge MA 02138 & via Zoom \nIn recent years\, a remarkable paradigm shift has occurred in understanding quantum observables in particle physics and cosmology\, revealing their emergence from underlying novel mathematical objects known as positive geometries. The conference will center on the amplituhedron—the first and major example of a positive geometry. Building on the work of Lusztig and Postnikov on the positive Grassmannian\, the physicists Arkani-Hamed and Trnka introduced the amplituhedron in 2013 as a geometric object that “explains” the so-called BCFW recurrence for scattering amplitudes in N = 4 super Yang Mills theory (SYM). Simultaneously\, cluster algebras\, originally introduced by Fomin and Zelevinsky to study total positivity\, have been revealed to have a crucial role in describing singularities of N = 4 SYM scattering amplitudes. Thus\, one can use ideas from quantum field theory (QFT) to connect cluster algebras to positive geometries\, and in particular to the amplituhedron. Additionally\, QFT can also be used to discover new examples of positive geometries. The conference will bring together a wide range of mathematicians and physicists both to draw new connections within algebraic combinatorics and geometry and to advance our physical understanding of scattering amplitudes and QFT. \nThe conference features: Introductory Lectures\, an Open Problems Forum\, Emerging Scholars Talks\, and talks by experts in the fields. \n  \nConference Videos (Youtube Playlist) \n  \nConfirmed Speakers: \n\nEvgeniya Akhmedova\, Weizmann Institute of Science\nNima Arkani-Hamed\, IAS\nPaolo Benincasa\, MPI\nNick Early\, Weizmann Institute of Science\nCarolina Figueiredo\, Princeton University\nYu-tin Huang\, National Taiwan University\nDani Kaufman\, University of Copenhagen\nChia-Kai Kuo\, National Taiwan University\nThomas Lam\, University of Michigan\nYelena Mandelshtam\, UC Berkeley\nShruti Paranjape\, UC Davis\nLizzie Pratt\, UC Berkeley\nLecheng Ren\, Brown University\nSebastian Seemann\, KU Leuven\nKhrystyna Serhiyenko\, University of Kentucky\nMelissa Sherman-Bennett\, MIT & UC Davis\nMarcus Spradlin\, Brown University\nRan Tessler\, Weizmann Institute of Science\nHugh Thomas\, Université du Québec à Montréal\nJaroslav Trnka\, UC Davis\nAnastasia Volovich\, Brown University\n\nOrganizers: \n\nMatteo Parisi\, Harvard CMSA\nLauren Williams\, Harvard Mathematics\n\nParticipants (PDF) \nThis event is co-funded by the National Science Foundation. \nLimited funding to help defray travel expenses is available for graduate students and recent PhDs. If you are a graduate student or postdoc and would like to apply for support\, please register above and send an email to amplituhedra@cmsa.fas.harvard.edu no later than Friday\, April 19\, 2024. \nPlease include your name\, address\, current status\, university affiliation\, citizenship\, and area of study. F1 visa holders are eligible to apply for support. If you are a graduate student\, please send a brief letter of recommendation from a faculty member to explain the relevance of the conference to your studies or research. If you are a postdoc\, please include a copy of your CV. \n\nSCHEDULE (pdf download) \nWednesday\, May 29\, 2024\n8:30 – 9:00 am\nRegistration and Breakfast \n9:00 – 10:00 am\nJaroslav Trnka\, UC Davis\nTitle: Amplituhedron\nAbstract: I will review basics of the Amplituhedron\, connection to the positive Grassmannian on the mathematical side\, and the scattering amplitudes on the physics side. \n10:00 – 10:15 am\nCoffee Break \n10:15 – 11:15 am\nvia Zoom\nKhrystyna Serhiyenko\, University of Kentucky\nTitle: Introduction to Cluster Algebras\nAbstract: Cluster algebras is a class of commutative rings with an intricate combinatorial structure. They were introduced by Fomin and Zelevinsky in 2002 to study total positivity and canonical basis in Lie Theory\, but quickly evolved into a highly active research area with surprising connections to numerous other areas of mathematics and physics.\nIn this course we will introduce cluster algebras and discuss their basic properties including positivity and Laurent phenomenon. We will also review cluster structures coming from coordinate rings of Grassmannians and the combinatorics of plabic graphs. \n11:15 – 11:30 am\nCoffee Break \n11:30 – 12:30 pm\nThomas Lam\, University of Michigan\nTitle: Introductory Lecture on Positive Geometries\nAbstract: Positive geometries are semialgebraic spaces that appear in the study of scattering amplitudes. Examples include polytopes\, totally nonnegative parts of flag varieties\, and conjecturally\, the amplituhedron. We will give a broad introduction to positive geometries\, and to their canonical forms. \n12:30 – 2:00 pm\nLunch Break \n2:00 – 2:50 pm\nAnastasia Volovich\, Brown University\nTitle: Scattering Amplitudes and Cluster Algebras\nAbstract: I will review some of the deep connections between cluster algebras and the (loop level) scattering amplitudes in N=4 super Yang-Mills theory\, focusing on the cases of n=6 and 7 particles where the corresponding Grassmannian cluster algebras Gr(4\,n) are finite and certain features of the amplitudes are known or believed to be true to all loop order. \n2:50 – 3:00 pm\nCoffee Break \n3:00 – 3:50 pm\nMarcus Spradlin\, Brown University\nTitle: Scattering Amplitudes\, Positive Geometry and the Amplituhedron\nAbstract: I will review the status of (loop level) scattering amplitudes in N=4 super Yang-Mills theory for n>7\, where the corresponding Grassmannian cluster algebras Gr(4\,n) are infinite and novel features emerge\, notably the appearance of certain “marginally positive” algebraic functions of cluster variables. \n3:50 – 4:00 pm\nCoffee Break \n4:00 – 4:30 pm\nCarolina Figueiredo\, Princeton University\nTitle: All-order splits and multi-soft limits for particle and string amplitude\nAbstract: The most important aspects of scattering amplitudes have long been thought to be associated with their poles. Recently a very different sort of “split” factorizations for a wide range of particle and string tree amplitudes have been discovered away from poles. In this talk\, I will explain how natural properties of the binary geometry of the curve integral formulation for scattering amplitudes for Tr$(\Phi^3)$ theory give a simple\, conceptual origin for these splits\, that generalizes them to all orders in the topological expansion. I will also explain how the splits allow us to access and compute loop-integrated multi-soft limits for particle and string amplitudes in Tr$(\Phi^3)$ theory\, the non-linear sigma model and Yang-Mills theory. \n4:30 – 5:15 pm\nYelena Mandelshtam\, UC Berkeley\nTitle: Combinatorics of m=1 Grasstopes\nAbstract: A Grasstope is a linear projection of the totally nonnegative Grassmannian to a smaller Grassmannian. This is a generalization of the amplituhedron\, a geometric object of great importance to calculating scattering amplitudes in physics. The amplituhedron is a Grasstope arising from a totally positive linear map. While amplituhedra are relatively well-studied\, much less is known about general Grasstopes. In this talk\, I will discuss combinatorics and geometry of Grasstopes in the m=1 case. In particular\, I will show that they can be characterized as unions of cells of a hyperplane arrangement satisfying a certain sign variation condition and argue that amplituhedra are (in a certain sense) minimal Grasstopes. This is based on joint work with Dmitrii Pavlov and Lizzie Pratt. \n5:30 – 6:30 pm\nWelcome Reception \n  \nThursday\, May 30\, 2024 \n8:30 – 9:00 am\nBreakfast \n9:00 – 10:00 am\nNima Arkani-Hamed\, IAS\nTitle: Surface Kinematics and THE all-loop integrand for gluon amplitudes \n10:00 – 10:30 am\nCoffee Break \n10:30 – 11:20 am\nHugh Thomas\, Université du Québec à Montréal\nTitle: u-equations from finite dimensional algebras\nAbstract: In this talk\, I will explain how to write down and solve a system of u-equations associated to any finite dimensional algebra with finitely many indecomposable representations. These vastly generalize the system of equations written down by Koba and Nielsen in 1969\, which from our point of view are associated to the representation theory of a Dynkin type A quiver. I will discuss features of the resulting solution spaces\, including connections to tau-tilting theory\, and the relationships that exist among different spaces of solutions. I will also say something about how different choices of finite-dimensional algebra put us in (i) the setting of cluster algebras\, (ii) the Grassmannian combinatorics of non-kissing complexes\, or (iii) the curves-on-surfaces model directly relevant to amplitudes. This talk reports on joint work with Nima Arkani-Hamed\, Hadleigh Frost\, Pierre-Guy Plamondon\, and Giulio Salvatori. \n11:20 – 11:30 am\nCoffee Break \n11:30 – 12:20 pm\nDani Kaufman\, University of Copenhagen\nTitle: Affine Cluster Algebras\nAbstract: Affine cluster algebras form the simplest examples of non-finite type cluster algebras. While they have infinitely many clusters\, they are still mutation finite and have essentially one mutation sequence which produces infinitely many clusters. I will give an introduction to these cluster algebras by comparing them with finite cluster algebras. I will also show how some structures similar to finite type cluster algebras appear “in the limit” along this infinite mutation sequence. If time I will also mention how the “infinite cluster variables” which live in the limit are related to the algebraic letters appearing in the symbol alphabet for 8 particle N=4 SYM amplitudes. \n12:30-12:45 pm\nGroup Photo\, 20 Garden Street\, front entrance stairs outside building \n12:45 – 2:00 pm\nLunch Break \n2:00 – 2:50 pm\nvia Zoom\nRan Tessler\, Weizmann Institute of Science\nTitle: The magic number for the m=2 amplituhedron\nAbstract: We will start by reviewing the amplituhedron and its tilings.\nWe will then show that all tilings of the m=2 amplituhedron have the same cardinality (“the magic number”)\, proving the m=2 case of a conjecture that the same holds for all even-m amplituhedra. If time permits we will discuss related results and consequences.\nBased on a joint work with Parisi\, Sherman-Bennett and Williams. \n2:50 – 3:00 pm\nCoffee Break \n3:00 – 3:50 pm\nMelissa Sherman-Bennett\, MIT & UC Davis\nTitle: Cluster algebras and tilings of amplituhedra\nAbstract: Physicists Arkani-Hamed and Trnka introduced the amplituhedron to better understand scattering amplitudes in N=4 super Yang-Mills theory. The amplituhedron is the image of the totally nonnegative Grassmannian under the “amplituhedron map”. Examples of amplituhedra include cyclic polytopes\, the totally nonnegative Grassmannian itself\, and cyclic hyperplane arrangements. Of primary interest to physics are tilings of amplituhedra\, which are roughly analogous to subdivisions of polytopes. I will discuss joint work with Even-Zohar\, Lakrec\, Parisi\, Tessler and Williams on BCFW tilings of m=4 amplituhedra and the surprising connection between these tilings and the cluster algebra structure of the Grassmannian. \n3:50 – 4:00 pm\nCoffee Break \n4:00 – 5:30 pm\nOpen Problems Forum \n6:00 – 8:00 pm\nConference Dinner (by invitation) \n  \nFriday\, May 31\, 2024 \n8:30 – 9:00 am\nBreakfast \n9:00 – 10:00 am\nYu-tin Huang\, National Taiwan University\nTitle: Chambers and all loop geometry for four-point correlators\nAbstract: The all loop amplituhedron for N=4 SYM (and ABJM theory) can be recast into the notion of loop fibration over tree geometry. This leads to a further dissection of the tree geometry into “chambers”\, whose boundaries represents when the associated loop-form changes. In this talk I will present a new geometry associated with the all loop four-point correlator of N=4 SYM\, where similar description is present. Interestingly\, at four-loops\, this gives a first example where the chamber form is rational even though it’s loop form contains elliptic integrals. \n10:00 – 10:15 am\nCoffee Break \n10:15 – 12:30 am\nEmerging Scholar Talks \n10:15 – 10:40 am\nEvgeniya Akhmedova\, Weizmann Institute of Science\nTitle: The tropical amplituhedron\nAbstract: The Amplituhedron is a geometric object discovered recently by Arkani-Hamed and Trnka\, that provides a completely new direction for calculating scattering amplitudes in quantum field theory. We define a tropical analogue of this object\, the tropicial amplituhedron and study its structure and boundaries. It can be considered as both the tropical limit of the amplituhedron and a generalization of the tropical positive Grassmannian. \n10:40 – 11:10 am\nLizzie Pratt\, UC Berkeley\nTitle: The Chow-Lam Form\nAbstract: The classical Chow form encodes any projective variety by one equation. We introduce the Chow-Lam form for subvarieties of a Grassmannian. By evaluating the Chow-Lam form at twistor coordinates\, we obtain universal projection formulas\, which were pioneered by Thomas Lam for positroid varieties in the study of amplituhedra. This is joint work with Bernd Sturmfels. \n11:10– 11:30 am\nSebastian Seemann\, KU Leuven\nTitle: Vandermonde cells as positive geometries\nAbstract: Vandermonde cells represent semialgebraic subsets of R^n\, characterized as the image of a simplex under the Vandermonde map. However\, within the realm of positive geometry\, several challenges arise in establishing canonical forms for these cells. These include issues such as non-normal boundaries\, non-transversal intersections\, and singularities of boundary curves. Even more difficulties appear when considing the limiting Vandermonde cell\, which is not semi-algebraic and thus doesn’t fit within the standard framework of positive geometries. In this presentation\, I will first review the notion of Polypols and their canonical forms\, examining the complexities encountered when dealing with Vandermonde cells. In particular\, I will explain what goes wrong in the case of Vandermonde cells and which obstructions we can deal with. \n11:30 – 11:40 am\nCoffee break \n11:40 – 12:10 pm\nChia-Kai Kuo\, National Taiwan University\nTitle: Geometric transition from maximal SYM to ABJM\nAbstract: Recently\, the ABJM amplituhedron has been proposed\, encoding all-loop and all-multiplicity ABJM amplitudes. It is constructed by slightly modifying the original definition. In this talk\, I will explore the significance of these modifications in transitioning theoretical models from super Yang-Mills theory to ABJM theory. A key focus will be on how symplectic reduction and the overall sign change in the positivity conditions ensure the consistency of ABJM amplitudes. Additionally\, I will discuss some distinct features of this geometry. \n12:10– 12:30 pm\nLecheng Ren\, Brown University\nTitle: Symbol alphabets from tensor diagrams\nAbstract: We propose to use tensor diagrams and the Fomin-Pylyavskyy conjectures to explore the connection between symbol alphabets of n-particle amplitudes in planar N= 4 Yang-Mills theory and certain polytopes associated to the Grassmannian Gr(4\, n). We show how to assign a web (a planar tensor diagram) to each facet of these polytopes. Webs with no inner loops are associated to cluster variables (rational symbol letters). For webs with a single inner loop we propose and explicitly evaluate an associated web series that contains information about algebraic symbol letters. In this manner we reproduce the results of previous analyses of n ≤ 8\, and find that the polytope C(4\,9) encodes all rational letters\, and all square roots of the algebraic letters\, of known nine-particle amplitudes. \n12:30 – 2:00 pm\nLunch Break \n2:00 – 2:50 pm\nvia Zoom\nPaolo Benincasa\,  MPI\nTitle: Cosmological Polytopes & Beyond\nAbstract: Together with being the source of the most profound questions in fundamental physics\, cosmology turns out to be an arena from where novel combinatorial structures emerge. In this talk\, I will give a gentle introduction to the cosmological polytopes\, describing the so-called Bunch-Davies wavefunction for a large class of scalar theories\, and how it can be used to define and characterize less conventional objects\, named optical polytopes and weighted cosmological polytopes\, which provide examples of non-convex and weighted geometries respectively. \n2:50 – 3:00 pm\nCoffee Break \n3:00 – 3:45 pm\nShruti Paranjape\, UC Davis\nTitle: Loops in a loop expansion\nAbstract: In a paper by Arkani-Hamed\, Henn and Trnka\, it was shown that the amplituhedron construction of N=4 SYM can be recast in terms of negative geometries with a certain hierarchy of loops (closed cycles) in the space of loop momentum twistors. Furthermore\, using differential equation methods\, it was possible to calculate and resum integrated expressions and obtain strong coupling results. In this talk\, we provide a more general framework for the loops of loops expansion and outline a powerful method for the determination of differential forms for higher-order geometries. In particular\, we will focus on the case of 1 closed cycle in loop space and select integrated results. \n3:45 – 4:30 pm\nNick Early\, Weizmann Institute of Science\nTitle: Minimal Kinematics on $\mathcal{M}_{0\,n}$\, and beyond\nAbstract: Minimal Kinematics (MK) identifies kinematic degenerations of the CHY scattering potential where the critical points are given by rational formulas. These rest on the Horn uniformization of Kapranov-Huh; they are specified combinatorially by 2-trees. On the other hand\, Planar Kinematics (PK) identifies the locus in $M_{0\,n}$ which is fixed by cyclic permutation.  Combining MK and PK realizes a maximally thin relative of the associahedron known as the PK polytope; it is a reflexive polytope\, and its polar dual\, the root polytope\, has volume a Catalan number. In this talk\, we start by exploring MK and PK on the moduli space $M_{0\,n}$.  We explain how this story generalizes to moduli spaces $X(k\,n)$ of points in projective space $\mathbb{P}^{k-1}$\, to CEGM amplitudes and beyond. \n4:30 – 5:00 pm\nCoffee and Farewell \n  \n \n  \nAbout the image: \n\nLeft: the 3-dimensional associahedron\, Fomin and Zelevinsky\n\nCenter: artistic depiction of the amplituhedron\, Gilmore\nRight: Schlegel diagram of a hypersimplex\, Ziegler
URL:https://cmsa.fas.harvard.edu/event/amplituhedra2024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Conference
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/amplituhedron_cluster-algebras_posgeometry.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240624T080000
DTEND;TZID=America/New_York:20240626T170000
DTSTAMP:20260716T055602
CREATED:20240415T161428Z
LAST-MODIFIED:20241212T160959Z
UID:10003355-1719216000-1719421200@cmsa.fas.harvard.edu
SUMMARY:Workshop on Fibration and Degeneration in Calabi-Yau Geometry
DESCRIPTION:Workshop on Fibration and Degeneration in Calabi-Yau Geometry \nDates: June 24-26\, 2024 \nLocation: Harvard CMSA\, 20 Garden Street\, Cambridge\, MA 02138 \nOrganizer: Chuck Doran\, Harvard CMSA \n\nCalabi-Yau manifolds occupy a central place in geometry. Their critical role as the cut-case between basic Fano building blocks and the zoo of General Type manifolds is key to the wide variety of important applications of Calabi-Yau geometry to theoretical physics. In turn\, ideas from theoretical physics\, such as Mirror Symmetry\, help shape investigations in Calabi-Yau geometry \nThis workshop focuses on a structural feature of Calabi-Yau geometry identified a decade ago by Doran\, Harder\, and Thompson. It is an organizing principle that conjecturally underlies any and all constructions of mirror pairs of Calabi-Yau manifolds. Put simply\, the DHT Mirror Symmetry slogan is: “Degeneration is mirror to fibration.” \n\n\nConfirmed Speakers: \n\nDavid Favero (University of Minnesota)\nAndrew Harder (Lehigh University)\nJesse Huang (University of Alberta)\nMohsen Karkheiran* (University of Alberta)\nMatt Kerr* (Washington University in St. Louis)\nThorsten Schimannek* (Utrecht University)\nMichael Schultz (Virginia Tech)\nAlan Thompson (Loughborough University)\nFenglong You (University of Nottingham & ETH Zurich)\n\n*= via Zoom \n  \nSchedule \nMonday\, June 24\, 2024 \n9:30 – 10:00 am: Breakfast \n10:00 – 11:00 am\nSpeaker: Alan Thompson\, Loughborough University\nTitle: Mirror symmetry for fibrations and degenerations of K3 surfaces\nAbstract: I will describe recent progress\, joint with Luca Giovenzana\, on the DHT problem for K3 surfaces. I will give an lattice-theoretic definition for when a Tyurin degeneration of K3 surfaces and an elliptically-fibred K3 surface\, with an appropriate splitting of the base\, form a mirror pair. I will then explain how this definition is compatible with lattice polarised mirror symmetry for K3 surfaces and with Fano-LG mirror symmetry for (quasi) del Pezzo surfaces. The upshot will be a concrete statement of the DHT conjecture for K3 surfaces. \n12:00 – 1:00: Lunch \n1:00 – 2:00 pm\nSpeaker: David Favero\, University of Minnesota\nTitle: Homotopy Path Algebras and Resolutions\nAbstract: A homotopy path algebra is like a directed version of the group ring on a fundamental group.  One can imagine a directed graph (quiver) embedded in a topological space and considering the path algebra up to homotopy.  Alternatively\, one can think of homotopy classes of directed paths in a stratified topological space.  I will introduce homotopy path algebras and describe their connections to mirror symmetry and resolutions of coherent sheaves on toric varieties. \n3:00 – 4:00 pm\nSpeaker: Andrew Harder\, Lehigh University\nTitle: Tropical Hodge theory for hypersurfaces and Clarke duality\nAbstract: Results of Itenberg\, Katzarkov\, Mikhalkin\, and Zharkov (IKMZ) show that if a projective variety admits a smooth tropicalization\, then there is a collection of sheaves on its tropicalization that can be used to compute its Hodge numbers. However\, smooth tropicalizations fail to exist even in the case of toric hypersurfaces. In work with Sukjoo Lee\, we show that for any toric hypersurface\, an analogue of IKMZ’s result holds. I’ll discuss this sheaf\, and how this allows us to prove that Clarke dual pairs of Landau-Ginzburg models satisfy a particular Hodge number duality. This is a vast generalization of work of Batyrev and Borisov from the 90s. \n4:00 – 4:30 pm: Coffee/Tea \n  \nTuesday\, June 25\, 2024 \n9:30 – 10:00 am: Breakfast \n10:00 – 11:00 am\nSpeaker: Matt Kerr\, Washington University in St. Louis\nTitle: Hypergeometric families and Beilinson’s conjectures\nAbstract: I will describe the construction of motivic cohomology classes on hypergeometric families of Calabi-Yau 3-folds using Hadamard convolutions. These are analogous to elements of the Mordell-Weil group for families of elliptic curves\, and produce solutions to certain inhomogeneous Picard-Fuchs equations. This is part of a joint project with Vasily Golyshev in which we numerically verify Beilinson’s conjectures in some new cases. \n12:00 – 1:00: Lunch \n1:00 – 2:00 pm\nSpeaker: Fenglong You\, University of Nottingham & ETH Zurich\nTitle: Theta functions in mirror symmetry\nAbstract: To obtain a mirror of a Calabi—Yau manifold using Gross—Siebert’s intrinsic mirror symmetry\, one considers a maximally unipotent monodromy degeneration of the Calabi—Yau and take proj of the degree zero part of a relative quantum cohomology ring associated with the degeneration. Theta functions form a canonical basis of the degree zero part of the relative quantum cohomology ring. Theta functions can also be defined in terms of punctured invariants of the broken line type. I will explain a variant of intrinsic mirror symmetry using orbifold invariants\, theta functions for general snc pairs and a relation with the DHT conjecture. \n3:00 – 4:00 pm\nSpeaker: Mohsen Karkheiran\, University of Alberta\nTitle: Emergence of Heterotic-Type II duality from DHT conjecture\nAbstract: The duality between Heterotic and Type IIA strings was conjectured in mid-90’s based on the properties of 4D N=2 field theories and solitonic strings in 6D. Here\, we show that this duality can also emerge from the DHT conjecture. We assume both IIA and IIB strings are compactified over toric Calabi-Yau threefolds which admit K3-fibrations with arbitrary polarizations. Then by applying the Hori-Vafa mirror symmetry to the “pieces” of these Calabi-Yau manifolds\, we will be able to derive the defining data for Heterotic strings. This approach works for any gauge group on the Heterotic side\, and we will show how it can be practically useful to derive the Heterotic dual for any toric Calabi-Yau threefolds in Type IIA or F-theory. \n4:00 – 4:30 pm: Coffee/Tea \n  \nWednesday\, June 26\, 2024 \n9:30 – 10:00 am: Breakfast \n10:00 – 11:00 am\nSpeaker: Thorsten Schimannek\, Utrecht University\nTitle: Enumerative geometry and modularity in two-modulus K3-fibered Calabi-Yau threefolds\nAbstract: Smooth M_m-polarized K3-fibered Calabi-Yau (CY) 3-folds have been classified in [DHNT] and [KT] in terms of the choice of a generalized functional invariant (GFI) and\, in the case m=1\, a generalized homological invariant (GHI). The resulting geometries generally exhibit a small number of complex structure moduli greater or equal to two. I will start my talk by discussing a concrete choice of these invariants that realizes (almost all of) the geometries with exactly two moduli and describe the structure of the corresponding moduli spaces. The corresponding variations of Hodge structure are entirely determined by the regular periods\, for which we obtain a generic expression in terms of m and three integers i\,j\,s. Using the form of this period and Batyrev-Borisov mirror symmetry I will then explicitly construct the corresponding mirror CY 3-folds with two Kaehler moduli and show consistency with the DHT conjecture. In the cases with s=0\, the mirror CY 3-folds are again K3-fibered but with a 2m-polarization. The generic form of the periods allows us to derive generic modular expressions for the A-model topological string free energies and we argue that those are a consequence of a Tyurin degeneration of the GFI with the central fiber being an M_m-polarized K3.\nThe talk is based on work in progress with Charles Doran and Boris Pioline. \n12:00 – 1:00: Lunch \n1:00 – 2:00 pm\nSpeaker: Michael Schultz\, Virginia Tech\nTitle: Mirror Symmetry from Irrationality Proofs and a Proposal for Local Invariants\nAbstract: While Apéry’s original proof of the irrationality of ζ(3) stunned the mathematics community in 1978\, subsequent generations of mathematicians (including a number of those at this workshop) have discovered geometric and modular structures underlying these irrationality proofs that are arguably even more striking. One such well known example are connections to modular pencils of elliptic curves and K3 surfaces and their Picard-Fuchs operators\, which exhibit maximally unipotent monodromy. These objects are respectively mirror dual to anticanonical divisors in certain del Pezzo surfaces and Fano threefolds\, and their Picard-Fuchs operators to the A-side connection on small quantum cohomology for these varieties. Although the Yukawa couplings calculated in classical mirror symmetry for elliptic curves and K3 surfaces are trivial\, I will show in this talk how a blend of the perspectives above allows one to define “virtual” Yukawa couplings for these families that are not trivial. It will be proposed that the utility of this perspective is in computing local invariants related to the mirror\, which recovers some known results in the literature and utilizes connections to work on the DHT conjecture and the twist construction of Doran & Malmendier. \n3:00 – 4:00 pm\nSpeaker: Jesse Huang\, University of Alberta\nTitle: An invitation to global toric mirror symmetry \n4:00 – 4:30 pm: Coffee/Tea \n  \n \n\n 
URL:https://cmsa.fas.harvard.edu/event/fibration/
LOCATION:20 Garden Street\, Cambridge\, MA 02138\, MA\, MA\, 02138\, United States
CATEGORIES:Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/calabi-yau-manifold-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240826T090000
DTEND;TZID=America/New_York:20240828T170000
DTSTAMP:20260716T055602
CREATED:20240209T180835Z
LAST-MODIFIED:20241212T152847Z
UID:10001874-1724662800-1724864400@cmsa.fas.harvard.edu
SUMMARY:Advances in Probability Theory and Interacting Particle Systems
DESCRIPTION:Advances in Probability Theory and Interacting Particle Systems\n\nA conference in honor of S. R. Srinivasa Varadhan.\n\nAugust 26 – August 28\, 2024\n\nHarvard Geological Lecture Hall\n\n\nConference Website: www.math.harvard.edu/event/math-conference-honoring-srinivasa-varadhan\n\nSpeakers\n\n\nInes Armendariz\, Universidad de Buenos Aires\nYuri Bakhtin\, Courant Institute\nGérard Ben Arous\, Courant Institute\nSourav Chatterjee\, Stanford University\nAmir Dembo\, Stanford University\nPeter K. Friz\, TU-Berlin\nNina Holden\, Courant Institute\nJiaoyang Huang\, University of Pennsylvania\nElena Kosygina\, City University of New York\nClaudio Landim\, IMPA\nEyal Lubetzky\, Courant Institute\nChiranjib Mukherjee\, Uni Münster\nStefano Olla\, Université Paris Dauphine\nJeremy Quastel\, University of Toronto\nKavita Ramanan\, Brown University\nAlejandro Ramirez\, NYU Shanghai\nFraydoun Rezakhanlou\, Berkeley\nSunder Sethuraman\, University of Arizona\nScott Sheffield\, MIT\nOfer Zeitouni\, Weizmann Institute\n\nOrganizers: Paul Bourgade (New York University\, Courant Institute) and Horng-Tzer Yau (Harvard University).\n\n\nSponsored by Harvard University Department of Mathematics and the Center of Mathematical Studies and Applications (CMSA).\n\nHarvard University is committed to maintaining a safe and healthy educational and work environment in which no member of the University community is\, on the basis of sex\, sexual orientation\, or gender identity\, excluded from participation in\, denied the benefits of\, or subjected to discrimination in any University program or activity. More information can be found here.
URL:https://cmsa.fas.harvard.edu/event/advances-in-probability-theory-and-interacting-particle-systems/
LOCATION:Harvard Geological Lecture Hall\, 24 Oxford St\, Cambridge\, 02138\, United States
CATEGORIES:Conference,Event
ATTACH;FMTTYPE=application/pdf:https://cmsa.fas.harvard.edu/media/Varadhan-Poster.pdf
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240903T090000
DTEND;TZID=America/New_York:20241101T170000
DTSTAMP:20260716T055602
CREATED:20240105T033600Z
LAST-MODIFIED:20250305T175957Z
UID:10001112-1725354000-1730480400@cmsa.fas.harvard.edu
SUMMARY:Mathematics and Machine Learning Program
DESCRIPTION:Mathematics and Machine Learning Program \nDates: September 3 – November 1\, 2024 \nLocation: Harvard CMSA\, 20 Garden Street\, Cambridge\, MA 0213 \nMachine learning and AI are increasingly important tools in all fields of research. Recent milestones in machine learning for mathematics include data-driven discovery of theorems in knot theory and representation theory\, the discovery and proof of new singular solutions of the Euler equations\, new counterexamples and lower bounds in graph theory\, and more. Rigorous numerical methods and interactive theorem proving are playing an important part in obtaining these results. Conversely\, much of the spectacular progress in AI has a surprising simplicity at its core. Surely there are remarkable mathematical structures behind this\, yet to be elucidated. \nThe program will begin and end with two week-long workshops\, and will feature focus weeks on number theory\, knot theory\, graph theory\, rigorous numerics in PDE\, and interactive theorem proving\, as well as a course on geometric aspects of deep learning.\n\n  \nSeptember 3–5\, 2024: Opening Workshop: AI for Mathematicians\, with Leon Bottou\, François Charton\, David McAllester\, Adam Wagner and Geordie Williamson.   A series of six lectures covering logic and theorem proving\, AI methods\, theory of machine learning\, two lectures on case studies in math-AI\, and a lecture and discussion on open problems and the ethics of AI in science.\nOpening Workshop Youtube Playlist \n\nSeptember 6–7\, 2024: Big Data Conference \n  \nSeptember 9–13\, 2024: Applying Machine Learning to Math\, with François Charton and Geordie Williamson\nPublic Lecture September 12\, 2024: Geordie Williamson\, University of Sydney: Can AI help with hard mathematics? (Youtube link)\nThe focus of this week will be on practical examples and techniques for the mathematics researcher keen to explore or deepen their use of AI techniques. We will have talks showcasing easily stated problems\, on which machine learning techniques can be employed profitably. These provide excellent toy examples for generating intuition. We will also have expert talks on some of the technical subtleties which arise. There are several instances where the accepted heuristics emerging from the study of large language models (LLM) and image recognition don’t appear to apply on mathematics problems\, and we will try to highlight these subtleties.\nApplying Machine Learning to Math Youtube Playlist \n  \nSeptember 16–20\, 2024: Number theory\, with Drew Sutherland\nThe focus of this week will be on the use of ML as a tool for finding and understanding statistical patterns in number-theoretic datasets\, using the recently discovered (and still largely unexplained) “murmurations” in the distribution of Frobenius traces in families of elliptic curves and other arithmetic L-functions as a motivating example.\nNumber Theory Youtube Playlist \n  \nSeptember 23–27\, 2024: Knot theory\, with Sergei Gukov\nKnot theory is a great source of labeled data that can be synthetically generated. Moreover\, many outstanding problems in knot theory and low-dimensional topology can be formulated as decision and classification tasks\, e.g. “Is the knot 123_45 slice?” or “Can two given Kirby diagrams be related by a sequence of Kirby moves?” During this focus week we will explore various ways in which AI can be applied to problems in knot theory and how\, based on these applications\, mathematical reasoning can advance development of AI algorithms. Another goal will be to develop formal knot theory libraries (e.g. contributions to mathlib) and to apply AI models to formal proof systems\, in particular in the context of knot theory.\nKnot Theory Youtube Playlist \n  \nSeptember 30: Teaching and Machine Learning Panel Discussion\, 3:30-5:30 pm ET \n  \nSeptember 30–October 4\, 2024: Graph theory and combinatorics\, with Adam Wagner\nThis week\, we will consider how machine learning can help us solve problems in combinatorics and graph theory\, broadly interpreted\, in practice. The advantage of these fields is that they deal with finite objects that are simple to set up using computers\, and programs that work for one problem can often be adapted to work for several other related problems as well. Many times\, the best constructions for a problem are easy to interpret\, making it simpler to judge how well a particular algorithm is performing. On the other hand\, there are lots of open conjectures that are simple to state\, for which the best-known constructions are counterintuitive\, making it perhaps more likely that machine learning methods can spot patterns that are difficult to understand otherwise.\nGraph Theory and Combinatorics Youtube Playlist \n  \nOctober 7–11\, 2024: More number theory\, with Drew Sutherland\nThe focus of this week will be on the use of AI as a tool to search for and/or construct interesting or extremal examples in number theory and arithmetic geometry\, using LLM-based genetic algorithms\, generative adversarial networks\, game-theoretic methods\, and heuristic tree pruning as alternatives to conventional local search strategies.\nMore Number Theory Youtube Playlist \n  \nOctober 14 –18\, 2024: Interactive theorem proving\nThis week we will discuss the use of interactive theorem proving systems such as Lean\, Coq and Isabelle in mathematical research\, and AI systems which prove theorems and translate between informal and formal mathematics.\nInteractive Theorem Proving Youtube Playlist \n  \nOctober 21–25\, 2024: Numerical Partial Differential Equations (PDE)\, with Tristan Buckmaster and Javier Gomez-Serrano\nThe focus of this week will be on constructing solutions to partial differential equations and dynamical systems (finite and infinite dimensional) more broadly defined. We will discuss several toy problems and comment on issues like sampling strategies\, optimization algorithms\, ill-posedness\, or convergence. We will also outline strategies about further developing machine-learning findings and turn them into mathematical theorems via computer-assisted approaches.\nNumerical PDEs Youtube Playlist \n  \nOctober 28–Nov. 1\, 2024: Closing Workshop: The closing workshop will provide a forum for discussing the most current research in these areas\, including work in progress and recent results from program participants.\nMath and Machine Learning Closing Workshop Youtube Playlist \n  \nSeptember 3–Nov. 1: Graduate topics in deep learning theory (Boston College) taught by Eli Grigsby\, held at the CMSA Tuesdays and Thursdays 2:30–3:45 pm Eastern Time. Course website (link).\nGraduate Topics in Deep Learning Youtube Playlist \nCourse description: This is a course on geometric aspects of deep learning theory. Broadly speaking\, we’ll investigate the question: How might human-interpretable concepts be expressed in the geometry of their data encodings\, and how does this geometry interact with the computational units and higher-level algebraic structures in various parameterized function classes\, especially neural network classes? During the portion of the course Sep. 3-Nov. 1\, the course will be presented as part of the Math and Machine Learning program at the CMSA in Cambridge. During that portion\, we will focus on the current state of research on mechanistic interpretability of transformers\, the architecture underlying large language models like Chat-GPT. \n\n\n\n\nPrerequisites: This course is targeted to graduate students and advanced undergraduates in mathematics and theoretical computer science. No prior background in machine learning or learning theory will be assumed\, but I will assume a degree of mathematical maturity (at the level of–say—the standard undergraduate math curriculum+ first-year graduate geometry/topology sequence)\n\n\n\n\n\nProgram Organizers \n\nFrancois Charton (Meta AI)\nMichael R. Douglas (Harvard CMSA)\nMichael Freedman (Harvard CMSA)\nFabian Ruehle (Northeastern)\nGeordie Williamson (Univ. of Sydney)\n\n\nProgram Schedule  \nMonday\n10:30–noon\nOpen Discussion\nRoom G10 \n12:00–1:30 pm\nGroup lunch\nCMSA Common Room \nTuesday\n2:30–3:45 pm\nTopics in deep learning theory\nRoom G10 \n4:00–5:00 pm\nOpen Discussion/Tea\nCMSA Common Room \nWednesday\n10:30 am–12:00 pm\nOpen Discussion\nRoom G10 \n2:00–3:00 pm\nNew Technologies in Mathematics Seminar\nRoom G10 \nThursday\n2:30–3:45 pm\nTopics in deep learning theory\nRoom G10 \nFriday\n10:30 am–12:00 pm\nOpen Discussion\nRoom G10 \n\nHarvard CMSA thanks Mistral AI for a generous donation of computing credit.
URL:https://cmsa.fas.harvard.edu/event/mml2024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Programs
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/Machine-Learning-Program-poster-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240903T100000
DTEND;TZID=America/New_York:20240905T160000
DTSTAMP:20260716T055602
CREATED:20240105T031946Z
LAST-MODIFIED:20240918T190637Z
UID:10001110-1725357600-1725552000@cmsa.fas.harvard.edu
SUMMARY:Mathematics and Machine Learning Program Opening Workshop
DESCRIPTION:Mathematics and Machine Learning Program Opening Workshop \nDates: September 3 – 5\, 2024 \nLocation: Room G10\, CMSA\, 20 Garden Street\, Cambridge MA & via Zoom Webinar \nAI for Mathematicians\, with Leon Bottou\, François Charton\, David McAllester\, Adam Wagner\, Boris Hanin\, and Geordie Williamson.  A series of 6 tutorial lectures introducing concepts of AI and of theorem proving\, with many case studies of AI applied to mathematics\, and including lectures and discussion sessions on open questions\, future prospects\, and ethical questions.\n  \nSpeakers \n\nLeon Bottou (Meta AI)\nFrançois Charton (Meta AI)\nMichael R. Douglas (Harvard CMSA)\nBoris Hanin (Princeton)\nDavid McAllester (TTIC)\nAdam Wagner (WPI)\nGeordie Williamson (University of Sydney)\n\nSchedule (link to downloadable pdf) \nVideos from the Opening Workshop (Youtube Link) \n\n\n\nTuesday Sep. 3\, 2024\n\n\n9:30–10:00 am\nMorning refreshments\n\n\n10:00–11:30 am\nMike Douglas: Overview of AI for mathematics\nSlides (pdf)\n\n\n11:30 am–12:00 pm\nDiscussion\n\n\n12:00–1:30 pm\nBreak\n\n\n1:30–2:30 pm\nDavid McAllester: Logic and formal methods\nSlides (pdf)\n\n\n2:30–3:00 pm\nCoffee break\n\n\n3:00–4:00 pm\nPanel Discussion: Automated mathematical discovery\n\n\n\n  \n\n\n\nWednesday Sep. 4\, 2024\n\n\n9:30–10:00 am\nMorning refreshments\n\n\n10:00–11:30 am\nBoris Hanin: Theory of Machine Learning\nSlides (pdf)\n\n\n11:30 am–12:00 pm\nDiscussion\n\n\n12:00–1:30 pm\nBreak\n\n\n1:30–2:30 pm\nAdam Wagner: Case studies I: Reinforcement learning and pattern finding\nSlides (pdf)\n\n\n2:30–3:00 pm\nCoffee break\n\n\n\n  \n\n\n\nThursday Sep. 5\, 2024\n\n\n9:30–10:00 am\nMorning refreshments\n\n\n10:00–11:30 am\nFrançois Charton (slides-pdf)\nand Geordie Williamson: Case studies II\n\n\n11:30 am–12:00 pm\nDiscussion\n\n\n12:00–1:30 pm\nBreak\n\n\n1:30–2:30 pm\nLeon Bottou: Open questions in AI\nSlides (pdf)\n\n\n2:30–3:00 pm\nCoffee break\n\n\n3:00–4:00 pm\nPanel Discussion: How might AI change mathematics?\n\n\n\n  \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mmlworkshop_924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Workshop
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/ML_Opening-workshop-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240905T160000
DTEND;TZID=America/New_York:20240905T170000
DTSTAMP:20260716T055602
CREATED:20240710T192944Z
LAST-MODIFIED:20241212T195515Z
UID:10003398-1725552000-1725555600@cmsa.fas.harvard.edu
SUMMARY:CMSA/Math Fall Gathering
DESCRIPTION:September 5\, 2024 \n4:00 pm \nCMSA Common Room\, 20 Garden Street\, Cambridge MA \nAll CMSA and Math affiliates are invited.
URL:https://cmsa.fas.harvard.edu/event/fallgathering2024/
LOCATION:CMSA 20 Garden Street Cambridge\, Massachusetts 02138 United States
CATEGORIES:Event
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/CMSA-2-600x338-1-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240906T090000
DTEND;TZID=America/New_York:20240907T170000
DTSTAMP:20260716T055602
CREATED:20240325T141950Z
LAST-MODIFIED:20250415T154033Z
UID:10003287-1725613200-1725728400@cmsa.fas.harvard.edu
SUMMARY:Big Data Conference 2024
DESCRIPTION:  \n \nYoutube Playlist \nOn September 6-7\, 2024\, the CMSA hosted the tenth annual Conference on Big Data. The Big Data Conference features speakers from the Harvard community as well as scholars from across the globe\, with talks focusing on computer science\, statistics\, math and physics\, and economics. \nLocation: Harvard University CMSA\, 20 Garden Street\, Cambridge & via Zoom \n  \nSpeakers: \n\nTianxi Cai\, Harvard Chan School\nRaj Chetty\, Harvard\nBianca Dumitrascu\, Columbia\nBoris Hanin\, Princeton\nPeter Hull\, Brown\nJamie Morgenstern\, U Washington\nKavita Ramanan\, Brown\nNeil Thompson\, MIT\nMelanie Weber\, Harvard\nKun-Hsing Yu\, Harvard Medical School\n\nOrganizers: \n\nRediet Abebe\, Harvard Society of Fellows\nMorgane Austern\, Harvard University Statistics\nMichael R. Douglas\, Harvard CMSA\nYannai Gonczarowski\, Harvard University Economics and Computer Science\nSam Kou\, Harvard University Statistics\n\nSCHEDULE (downloadable pdf) \nFriday\, Sep. 6\, 2024 \n9:00 am: Breakfast \n9:30 am: Introductions \n9:45–10:45 am\nSpeaker: Peter Hull\, Brown University\nTitle: Measuring Discrimination in Multi-Phase Systems\, with an Application to Child Protection\nAbstract: Large racial disparities have been documented in many high-stakes settings—such as employment\, health care\, housing\, and criminal justice—raising concerns of discrimination by individual decision-makers. At the same time\, there is growing understanding that a focus on individual decisions can yield an incomplete view of discrimination; an extensive theoretical literature shows how discrimination can arise and compound across multiple decision-makers in interconnected systems. We develop new empirical tools for studying discrimination in such multi-phase systems and apply them to the setting of foster care placement by child protective services. Leveraging the quasi-random assignment of two sets of decision-makers—initial hotline call screeners and subsequent investigators—we study how unwarranted racial disparities arise and propagate through this system. Using a sample of over 200\,000 maltreatment allegations\, we find that calls involving Black children are 55% more likely to result in foster care placement than calls involving white children with the same potential for future maltreatment in the home. Call screeners account for up to 19% of this unwarranted disparity\, with the remainder due to investigators. Unwarranted disparity is concentrated in cases with potential for future maltreatment\, suggesting that white children may be harmed by “underplacement” in high-risk situations. \n10:45–11:00 am: Break \n11:00 am –12:00 pm\nSpeaker: Jamie Morgenstern\, U Washington\nTitle: What governs predictive disparity in modern machine learning applications?\nAbstract: The deployment of statistical models in impactful environments is far from new—simple correlations have been used to guide decisions throughout the sciences\, health care\, political campaigns\, and in pricing financial instruments and other products for decades. Many such models\, and the decisions they supported\, were known to have different degrees of predictive power for different demographic groups. These differences had numerous sources\, including: limited expressiveness of the statistical models; limited availability of data from marginalized populations; noisier measurements of both features and targets from certain populations; and features with less mutual information about the prediction target for some populations than others.\nModern decision systems which use machine learning are more ubiquitous than ever\, as are their differences in performance for different populations of people. In this talk\, I will discuss some similarities and differences in the sources of differing performance in contemporary ML systems including facial recognition systems and those incorporating generative AI. \n12:00–1:30 pm: Lunch Break \n1:30–2:30 pm\nSpeaker: Kavita Ramanan\, Brown University\nTitle: Understanding High-dimensional Stochastic Dynamics on Realistic Networks\nAbstract: Large collections of randomly evolving particles that interact locally with respect to an underlying network model a variety of phenomena ranging from magnetism\, the spread of diseases\, neural and neuronal networks\, opinion dynamics and load balancing on computer networks. Due to their high-dimensional nature\, these systems are typically intractable to analyze exactly. Classical work\, falling under the rubric of mean-field approximations\, has mostly focused on the case when this interaction graph is dense.  However\, most real-world networks are sparse and often random. We describe a new approach to develop principled approximations for dynamics on realistic networks that beats the curse of dimensionality\, and illustrate its efficacy on a class of epidemiological models. This is based on joint works with Michel Davydov\, Ankan Ganguly and Juniper Cocomello. \n2:30–2:45 pm: Break \n2:45–3:45 pm\nSpeaker: Raj Chetty\, Harvard University\nTitle: The Science of Economic Opportunity: New Insights from Big Data\nAbstract: How can we improve economic opportunities for children growing up in low-income families? This talk will present findings from a recent set of studies that use various sources of big data — ranging from anonymized tax records to social network data — to understand the science of economic opportunity. Among other topics\, the talk will discuss how and why children’s chances of climbing the income ladder vary across neighborhoods\, the drivers of racial disparities in economic mobility\, how highly selective colleges may amplify the persistence of privilege\, and the role of social capital as a driver of upward mobility. The talk will conclude by giving examples of how academic research using big data is informing policy decisions from the local to federal level to expand opportunities for all. \n3:45–4:00 pm: Break \n4:00–5:00 pm\nSpeaker: Neil Thompson\nTitle: How Algorithmic Progress is driving progress in Big Data and AI\nAbstract: Algorithm improvement is one of the purest forms of innovation: it allows the same computational task to be achieved with far fewer resources by proposing clever new ways to do that computation. In this talk\, I will discuss the work that my lab has done tracking and quantifying progress across decades of algorithm research and practice. As I will show\, this algorithmic progress has often outpaced hardware improvement as the most important driver of progress in Big Data and AI. \n  \nSaturday\, Sep. 7\, 2024 \n9:00 am: Breakfast \n9:30 am: Introductions \n9:45–10:45 am\nSpeaker: Tianxi Cai\, Harvard Chan School\nTitle: Crowdsourcing with Multi-institutional EHR to Improve Reliability of Real World Evidence – Opportunities and Challenges\nAbstract: The wide adoption of electronic health records (EHR) systems has led to the availability of large clinical datasets available for discovery research. EHR data\, linked with bio- repository\, is a valuable new source for deriving real-word\, data-driven prediction models of disease risk and progression. Yet\, they also bring analytical difficulties especially when aiming to leverage multi-institutional EHR data. Synthesizing information across healthcare systems is challenging due to heterogeneity and privacy. Statistical challenges also arise due to high dimensionality in the feature space. In this talk\, I’ll discuss analytical approaches for mining EHR data to improve the reliability and generalizability of real world evidence generated from the analyses. These methods will be illustrated using EHR data from Mass General Brigham and Veteran Health Administration. \n10:45–11:00 am: Break \n11:00 am–12:00 pm\nSpeaker: Bianca Dumitrascu\, Columbia Data Science Institute\nTitle: Statistical machine learning for learning representations of embryonic development\nAbstract: During embryonic development\, single cells read in local information from their environments and use this information to move\, divide and specialize. As a result\, the environments themselves change.  However\, it remains unclear how gene expression programs interact with cell morphology and mechanical forces to orchestrate organogenesis in early embryos. Recent advances in single cell techniques and in toto imaging enable unique venues in exploring this link between genomics and biophysics\, which dynamically maps cells to organisms.\nIn this talk\, I will describe statistical machine learning frameworks aimed at understanding how tissue level mechanical and morphometric information impact gene expression patterns in spatio-temporal contexts. We use these tools to understand boundary formation in the early development of mouse embryos and to align data from light sheet recordings of pre-gastrulation development. \n12:00–1:30 pm: Lunch Break \n1:30–2:30 pm\nSpeaker: Melanie Weber\, Harvard Mathematics\nTitle: Data and Model Geometry in Deep Learning\nAbstract: Data with geometric structure is ubiquitous in machine learning. Often such structure arises from fundamental symmetries in the domain\, such as permutation-invariance in graphs and sets\, and translation-invariance in images. In this talk we discuss implications of this structure on the design and complexity of neural networks. Equivariant architectures\, which encode symmetries as inductive bias\, have shown great success in applications with geometric data\, but can suffer from instabilities as their depths increases. We propose a new architecture based on unitary group convolutions\, which allows for deeper networks with less instability. In the second part of the talk we discuss the impact of data and model geometry on the learnability of neural networks. We discuss learnability in several geometric settings\, including equivariant neural networks\, as well as learnability with respect to the geometry of the input data manifold. \n2:30–2:45 pm: Break \n2:45–3:45 pm\nSpeaker: Boris Hanin\, Princeton University\nTitle: Scaling Limits of Neural Networks\nAbstract: Neural networks are often studied analytically through scaling limits: regimes in which taking some structural network parameters (e.g. depth\, width\, number of training datapoints\, and so on) to infinity results in simplified models of learning. I will motivative and discuss recent results using several such approaches. I will emphasize both new theoretical insights into how model\, training data\, and optimizer impact learning and their practical implications for hyperparameter transfer. \n3:45–4:00 pm: Break \n4:00–5:00 pm\nSpeaker: Kun-Hsing Yu\, Harvard Medical School\nTitle: Foundation Models for Real-Time Cancer Diagnosis\nAbstract: Artificial intelligence (AI) is transforming the landscape of medical research and practice. Recent advances in microscopic image digitization\, foundation models\, and scalable computing infrastructure have opened new avenues for AI-enhanced cancer diagnosis. In this talk\, I will highlight recent breakthroughs in multi-modal AI systems for cancer pathology evaluation\, discuss integrative biomedical informatics methods that link cell morphology with molecular profiles\, and outline critical challenges in developing robust medical AI systems. \n  \n\nInformation about the 2023 Big Data Conference can be found here.
URL:https://cmsa.fas.harvard.edu/event/bigdata_2024/
LOCATION:20 Garden Street\, Cambridge\, MA 02138\, MA\, MA\, 02138\, United States
CATEGORIES:Big Data Conference,Conference,Event
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Big-Data-2024_8.5x11-1.png
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END:VCALENDAR