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DTSTART;TZID=America/New_York:20190819T083000
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SUMMARY:2019 Big Data Conference
DESCRIPTION:On August 19-20\, 2019 the CMSA hosted the fifth annual Conference on Big Data. The Conference will featured many 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. \nThe talks will take place in Science Center Hall D\, 1 Oxford Street. \nVideos can be found in the Youtube playlist.
URL:https://cmsa.fas.harvard.edu/event/2019-big-data-conference/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Big Data Conference,Conference,Event
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DTSTART;TZID=America/New_York:20190429T090000
DTEND;TZID=America/New_York:20190501T170000
DTSTAMP:20260508T100604
CREATED:20230715T174721Z
LAST-MODIFIED:20250304T214254Z
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SUMMARY:Conference on Algebraic Geometry\, Representation theory and Mathematical Physics
DESCRIPTION:From April 29 to May 1\, 2019 the CMSA will be hosting a Conference on Algebraic Geometry\, Representation theory and Mathematical Physics. This workshop is organized by Bong Lian (Brandeis) and Artan Sheshmani (CMSA) . The workshop will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA.   \nVideos\nSpeakers: \n\nDan Abramovich\, Brown\nRoman Bezrukavnikov\, MIT\nFedor Bogomolov\, NYU\nQile Chen\, Boston College\nDawei Chen\, Boston College\nAlexander Efimov\, Moscow\nPavel Etingof\, MIT\nMaksym Fedorchuk\, Boston College\nDennis Gaitsgory\, Harvard\nAmin Gholampour\, Maryland\nBrendan Hassett\, Brown\nLudmil Katzarkov\, Miami & Moscow\nSi Li\, Tsinghua\nAndrei Negut\, MIT\nYuri Tschinkel\, NYU\nWei Zhang\, MIT\n\n  \nMonday\, April 29 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 10:00am\nWei Zhang\, MIT\nTitle: The arithmetic fundamental lemma for diagonal cycles \nAbstract: I’ll recall the Gross–Zagier theorem and a high dimensional generalization\, the arithmetic Gan-Gross-Prasad conjecture\, which relates the height pairing of arithmetic diagonal cycles on certain shimura varieties to the first order derivative of certain L-functions.  The arithmetic fundamental lemma conjecture arises from the relative trace formula approach to this conjecture. I will recall the statement of the arithmetic fundamental lemma and outline a proof.\n\n\n10:00 – 10:30am\nBreak\n\n\n\n10:30 – 11:30am\nYuri Tschinkel\, NYU\nTitle: Equivariant birational geometry and modular symbols \nAbstract: We introduce new invariants in equivariant birational geometry and study their relation to modular symbols and cohomology of arithmetic groups (joint with M. Kontsevich and V. Pestun).\n\n\n11:30 – 1:30pm\nLunch\n\n\n\n1:30 – 2:30pm\nAlexander Efimov\, Moscow\nTitle: Torsionness for regulators of canonical extensions \nAbstract: I will sketch a generalization of the results of Iyer and Simpson arXiv:0707.0372 to the general case of a normal-crossings divisor at infinity.\n\n\n2:30 – 3:00pm\nBreak\n\n\n\n3:00 – 4:00pm\nAmin Gholampour\, Maryland\nTitle: Euler Characteristics of punctual quot schemes on threefolds \nAbstract: Let F be a homological dimension 1 torsion free sheaf on a nonsingular quasi-projective threefold. The first cohomology of the derived dual of F is a 1-dimension sheaf G supported on the singular locus of F. We prove a wall-crossing formula relating the generating series of the Euler characteristics of Quot(F\, n) and Quot(G\,n)\, where Quot(-\,n) denotes the quot scheme of length n quotients. We will use this relation in studying the Euler characteristics of the moduli spaces of stable torsion free sheaves on nonsingular projective threefolds. This is a joint work with Martijn Kool.\n\n\n4:00 – 4:30pm\nBreak\n\n\n\n4:30 – 5:30pm\nMaksym Fedorchuck\, BC\nTitle:  Stability of one-parameter families of weighted hypersurfaces \nAbstract:  We define a notion of stability for fibrations over a curve with generic fibers being weighted hypersurfaces (in some weighted projective space) generalizing Kollár’s stability for families of hypersurfaces in a projective space.  The stability depends on a choice of an effective line bundle on the parameter space of weighted hypersurfaces and different choices pick out different birational model of the total space of the fibration. I will describe enumerative geometry that goes into understanding these stability conditions\, and\, if time permits\, examples where this machinery can be used to produce birational models with good properties.  Joint work with Hamid Ahmadinezhad and Igor Krylov.\n\n\n\n  \nTuesday\, April 30 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 10:00am\nBrendan Hassett\, Brown\nTitle: Rationality for geometrically rational threefolds \nAbstract: We consider rationality questions for varieties over non-closed fields that become rational over an algebraic closure\, like smooth complete intersections of two quadrics.  (joint with Tschinkel)\n\n\n10:00 – 10:30am\nBreak\n\n\n\n10:30 – 11:30am\nDennis Gaitsgory\, Harvard\nTitle: The Fundamental Local Equivalence in quantum geometric Langlands \nAbstract: The Fundamental Local Equivalence is statement that relates the q-twisted  Whittaker category of the affine Grassmannian for the group G and the category of modules over the Langlands dual “big” quantum group. The non-triviaiity of the statement lies is the fact that the relationship between the group and its  dual is combinatorial\, so to prove the FLE one needs to express both sides in combinatorial terms. In the talk we will indicate the proof of a related statement for the “small” quantum group. The combinatorial link is provided by the category of factorization modules over a certain factorization algebra\, which in itself is a geometric device that concisely encodes the root data.\n\n\n11:30 – 1:00pm\nLunch\n\n\n\n1:00- 2:00pm\nAndrei Negut\, MIT\nTitle: AGT relations in geometric representation theory \nAbstract: I will survey a program that seeks to translate the Alday-Gaiotto-Tachikawa correspondence (between gauge theory on R^4 and conformal field theory) into the language of algebraic geometry. The objects of study become moduli spaces of sheaves on surfaces\, and the goal is to connect them with the W-algebra of type gl_n.\n\n\n2:00 – 2:15pm\nBreak\n\n\n\n2:15 – 3:15pm\nDan Abramovich\, Brown\nTitle: Resolution in characteristic 0 using weighted blowing up \nAbstract: Given a variety $X$\, one wants to blow up the worst singular locus\, show that it gets better\, and iterate until the singularities are resolved. \nExamples such as the whitney umbrella show that this iterative process cannot be done by blowing up smooth loci – it goes into a loop. \nWe show that there is a functorial way to resolve varieties using \emph{weighted} blowings up\, in the stack-theoretic sense. To an embedded variety $X \subset Y$ one functorially assigns an invariant $(a_1\,\ldots\,a_k)$\, and a center locally of the form $(x_1^{a_1} \, \ldots \, x_k^{a_k})$\, whose stack-theoretic weighted blowing up has strictly smaller invariant under the lexicographic order. \nThis is joint work with Michael Tëmkin (Jerusalem) and Jaroslaw Wlodarczyk (Purdue)\, a side product of our work on functorial semistable reduction. A similar result was discovered by G. Marzo and M. McQuillan.\n\n\n3:15 – 3:30pm\nBreak\n\n\n\n3:30 – 4:30pm\nFedor Bogomolov\, NYU\nTitle: On the base of a Lagrangian fibration for a compact hyperkahler manifold. \nAbstract: In my talk I will discuss our proof with N. Kurnosov that the base of such fibration for complex projective manifold hyperkahler manifold of dimension $4$ is always a projective plane $P^2$. In fact we show that the base of such fibration can not have a singular point of type $E_8$. It was by the theorem of Matsushita and others that only quotient singularities can occur and if the base is smooth then the it is isomorphic to $P^2$. The absence of other singularities apart from $E_8$ has been already known and we show that $E-8$ can not occur either. Our method can be applied to other types of singularities for the study of  Lagrangian fibrations in higher dimensions More recently similar result was obtained by Huybrechts and Xu.\n\n\n4:30 – 4:45pm\nBreak\n\n\n\n4:45 – 5:45pm\nDawei Chen\, BC\nTitle: Volumes and intersection theory on moduli spaces of Abelian differentials \nAbstract: Computing volumes of moduli spaces has significance in many fields. For instance\, Witten’s conjecture regarding intersection numbers on moduli spaces of Riemann surfaces has a fascinating connection to the Weil-Petersson volume\, which motivated Mirzakhani to give a proof via Teichmueller theory\, hyperbolic geometry\, and symplectic geometry. In this talk I will introduce an analogue of Witten’s intersection numbers on moduli spaces of Abelian differentials to compute the Masur-Veech volumes induced by the flat metric associated with Abelian differentials. This is joint work with Moeller\, Sauvaget\, and Zagier (arXiv:1901.01785).\n\n\n\n  \nWednesday\, May 1 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 10:00am\nPavel Etingof\, MIT\nTitle: Short star-products for filtered quantizations \nThis is joint work with Eric Rains and Douglas Stryker.\n\n\n10:00 – 10:30am\nBreak\n\n\n\n10:30 – 11:30am\nRoman Bezrukavnikov\, MIT\nTitle: Stability conditions and representation theory \nAbstract: I will recall the concept of real variation of stabilities (introduced in my work with Anno and Mirkovic)\nand its relation to modular Lie algebra representations. I will also address a potential generalization of that picture\nto modular representations of affine Lie algebras related to the classical limit of geometric Langlands duality and its local counterpart.\n\n\n11:30 – 11:45am\nBreak\n\n\n\n11:45 – 12:45pm\nQile Chen\, BC\nTitle: Counting curves in critical locus via logarithmic compactification \nAbstract: An R-map consists of a pre-stable map to possibly non-GIT quotient together with sections of certain spin bundles. The moduli of R-maps are in general non-compact. When the target of R-maps is equipped with a super-potential W with compact critical locus\, using Kiem-Li cosection localization it has been proved by many authors in various settings that the virtual cycle of R-maps can be represented by the cosection localized virtual cycle which is supported on the proper locus consisting of R-maps in the critical locus of W. Though the moduli of R-maps is equipped with a natural torus action by scaling of the spin bundles\, the non-compactness of the R-maps moduli makes such powerful torus action useless. \nIn this talk\, I will introduce a logarithmic compactification of the moduli of R-maps using certain modifications of stable logarithmic maps. The logarithmic moduli space carries a canonical virtual cycle from the logarithmic deformation theory. In the presence of a super-potential with compact critical locus\, it further carries a reduced virtual cycle. We prove that (1) the reduced virtual cycle of the compactification can be represented by the cosection localized virtual cycle; and (2) the difference of the canonical and reduced virtual cycles is another reduced virtual cycle supported along the logarithmic boundary. As an application\, one recovers the Gromov-Witten invariants of the critical locus as the invariants of logarithmic R-maps of its ambient space in an explicit form. The latter can be calculated using the spin torus action. \nThis is a joint work with Felix Janda and Yongbin Ruan.\n\n\n12:45 – 2:30pm\nLunch\n\n\n\n2:30 – 3:30pm\nSi Li\, Tsinghua\nTitle: Semi-infinite Hodge structure: from BCOV theory to Seiberg-Witten geometry \nAbstract: I will explain how the semi-infinite Hodge theory extends Kodaira-Spencer gravity (Bershadsky-Cecotti-Ooguri-Vafa theory of B-twisted closed topological string field theory) into a full solution of Batalin-Vilkovisky master equation. This allows us to formulate quantum B-model via a rigorous BV quantization method and construct integrable hierarchies arising naturally from the background symmetry. In the second part of the talk\, I will explain the recent discovery of the connection between K.Saito’s primitive form and 4d N=2 Seiberg-Witten geometry arising from singularity theory.\n\n\n3:30 – 4:00pm\nBreak\n\n\n\n4:00 – 5:00pm\nLudmil Katzarkov\, Moscow\nTitle: PDE’s non commutative  motives and HMS. \nAbstract: In this talk we will discuss the theory of central manifolds and the new structures in geometry it produces. Application to Bir.  Geometry will be discussed.\n\n\n\n 
URL:https://cmsa.fas.harvard.edu/event/conference-on-algebraic-geometry-representation-theory-and-mathematical-physics/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Conference,Event
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DTSTART;TZID=America/New_York:20190415T091500
DTEND;TZID=America/New_York:20190417T160000
DTSTAMP:20260508T100604
CREATED:20230715T173507Z
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SUMMARY:Workshop on Invariance and Geometry in Sensation\, Action and Cognition
DESCRIPTION:As part of the program on Mathematical Biology a workshop on Invariance and Geometry in Sensation\, Action and Cognition will take place on April 15-17\, 2019. \nLegend has it that above the door to Plato’s Academy was inscribed “Μηδείς άγεωµέτρητος είσίτω µον τήν στέγην”\, translated as “Let no one ignorant of geometry enter my doors”. While geometry and invariance has always been a cornerstone of mathematics\, it has traditionally not been an important part of biology\, except in the context of aspects of structural biology. The premise of this meeting is a tantalizing sense that geometry and invariance are also likely to be important in (neuro)biology and cognition. Since all organisms interact with the physical world\, this implies that as neural systems extract information using the senses to guide action in the world\, they need appropriately invariant representations that are stable\, reproducible and capable of being learned. These invariances are a function of the nature and type of signal\, its corruption via noise\, and the method of storage and use. \nThis hypothesis suggests many puzzles and questions: What representational geometries are reflected in the brain? Are they learned or innate? What happens to the invariances under realistic assumptions about noise\, nonlinearity and finite computational resources? Can cases of mental disorders and consequences of brain damage be characterized as break downs in representational invariances? Can we harness these invariances and sensory contingencies to build more intelligent machines? The aim is to revisit these old neuro-cognitive problems using a series of modern lenses experimentally\, theoretically and computationally\, with some tutorials on how the mathematics and engineering of invariant representations in machines and algorithms might serve as useful null models. \nIn addition to talks\, there will be a set of tutorial talks on the mathematical description of invariance (P.J. Olver)\, the computer vision aspects of invariant algorithms (S. Soatto)\, and the neuroscientific and cognitive aspects of invariance (TBA). The workshop will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. This workshop is organized by L. Mahadevan (Harvard)\, Talia Konkle (Harvard)\, Samuel Gershman (Harvard)\, and Vivek Jayaraman (HHMI). \nVideos\nTentative Speaker List: \n\nAlessandro Achille\, UCLA\nVijay Balasubramanian\, University of Pennsylvania\nJeannette Bohg\, Stanford\nEd Connor\, Johns Hopkins\nMoira Dillon\, NYU\nJacob Feldman\, Rutgers\nIla Fiete\, MIT\nSam Gershman\, Harvard\nGily Ginosar\, Weizmann Institute of Science\nLucia Jacobs\, UC Berkeley\nVivek Jayaraman\, HHMI\nTalia Konkle\, Harvard\nL. Mahadevan\, Harvard\nMichael McCloskey\, Johns Hopkins\nSam Ocko\, Stanford\nPeter Olver\, University of Minnesota\nAnitha Pasupathy\, University of Washington\nSandro Romani\, Janelia\nStefano Soatto\, UCLA\nTatyana Sharpee\,  Salk Institute\nDagmar Sternad\, Northeastern\nElizabeth Torres\, Rutgers\n\nSchedule:\nMonday\, April 15 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 9:15am\nWelcome and Introduction\n\n\n\n9:15 – 10:00am\nVivek Jayaraman\nTitle: Insect cognition: Small tales of geometry & invariance \nAbstract: Decades of field and laboratory experiments have allowed ethologists to discover the remarkable sophistication of insect behavior. Over the past couple of decades\, physiologists have been able to peek under the hood to uncover sophistication in insect brain dynamics as well. In my talk\, I will describe phenomena that relate to the workshop’s theme of geometry and invariance. I will outline how studying insects —and flies in particular— may enable an understanding of the neural mechanisms underlying these intriguing phenomena.\n\n\n10:00 – 10:45am\nElizabeth Torres\nTitle: Connecting Cognition and Biophysical Motions Through Geometric Invariants and Motion Variability \nAbstract: In the 1930s Nikolai Bernstein defined the degrees of freedom (DoF) problem. He asked how the brain could control abundant DoF and produce consistent solutions\, when the internal space of bodily configurations had much higher dimensions than the space defining the purpose(s) of our actions. His question opened two fundamental problems in the field of motor control. One relates to the uniqueness or consistency of a solution to the DoF problem\, while the other refers to the characterization of the diverse patterns of variability that such solution produces. \nIn this talk I present a general geometric solution to Bernstein’s DoF problem and provide empirical evidence for symmetries and invariances that this solution provides during the coordination of complex naturalistic actions. I further introduce fundamentally different patterns of variability that emerge in deliberate vs. spontaneous movements discovered in my lab while studying athletes and dancers performing interactive actions. I here reformulate the DoF problem from the standpoint of the social brain and recast it considering graph theory and network connectivity analyses amenable to study one of the most poignant developmental disorders of our times: Autism Spectrum Disorders. \nI offer a new unifying framework to recast dynamic and complex cognitive and social behaviors of the full organism and to characterize biophysical motion patterns during migration of induced pluripotent stem cell colonies on their way to become neurons.\n\n\n10:45 – 11:15am\nCoffee Break\n\n\n\n11:15 – 12:00pm\nPeter Olver\nTitle: Symmetry and invariance in cognition — a mathematical perspective” \nAbstract: Symmetry recognition and appreciation is fundamental in human cognition.  (It is worth speculating as to why this may be so\, but that is not my intent.) The goal of these two talks is to survey old and new mathematical perspectives on symmetry and invariance.  Applications will arise from art\, computer vision\, geometry\, and beyond\, and will include recent work on 2D and 3D jigsaw puzzle assembly and an ongoing collaboration with anthropologists on the analysis and refitting of broken bones.  Mathematical prerequisites will be kept to a bare minimum.\n\n\n12:00 – 12:45pm\nStefano Soatto/Alessandro Achille\nTitle: Information in the Weights and Emergent Properties of Deep Neural Networks \nAbstract: We introduce the notion of information contained in the weights of a Deep Neural Network  and show that it can be used to control and describe the training process of DNNs\, and can explain how properties\, such as invariance to nuisance variability and disentanglement\, emerge naturally in the learned representation. Through its dynamics\, stochastic gradient descent (SGD) implicitly regularizes the information in the weights\, which can then be used to bound the generalization error through the PAC-Bayes bound. Moreover\, the information in the weights can be used to defined both a topology and an asymmetric distance in the space of tasks\, which can then be used to predict the training time and the performance on a new task given a solution to a pre-training task. \nWhile this information distance models difficulty of transfer in first approximation\, we show the existence of non-trivial irreversible dynamics during the initial transient phase of convergence when the network is acquiring information\, which makes the approximation fail. This is closely related to critical learning periods in biology\, and suggests that studying the initial convergence transient can yield important insight beyond those that can be gleaned from the well-studied asymptotics.\n\n\n12:45 – 2:00pm\nLunch\n\n\n\n2:00 – 2:45pm\nAnitha Pasupathy\nTitle: Invariant and non-invariant representations in mid-level ventral visual cortex \nMy laboratory investigates how visual form is encoded in area V4\, a critical mid-level stage of form processing in the macaque monkey. Our goal is to reveal how V4 representations underlie our ability to segment visual scenes and recognize objects. In my talk I will present results from two experiments that highlight the different strategies used by the visual to achieve these goals. First\, most V4 neurons exhibit form tuning that is exquisitely invariant to size and position\, properties likely important to support invariant object recognition. On the other hand\, form tuning in a majority of neurons is also highly dependent on the interior fill. Interestingly\, unlike primate V4 neurons\, units in a convolutional neural network trained to recognize objects (AlexNet) overwhelmingly exhibit fill-outline invariance. I will argue that this divergence between real and artificial circuits reflects the importance of local contrast in parsing visual scenes and overall scene understanding.\n\n\n2:45 – 3:30pm\nJacob Feldman\nTitle: Bayesian skeleton estimation for shape representation and perceptual organization \nAbstract: In this talk I will briefly summarize a framework in which shape representation and perceptual organization are reframed as probabilistic estimation problems. The approach centers around the goal of identifying the skeletal model that best “explains” a given shape. A Bayesian solution to this problem requires identifying a prior over shape skeletons\, which penalizes complexity\, and a likelihood model\, which quantifies how well any particular skeleton model fits the data observed in the image. The maximum-posterior skeletal model thus constitutes the most “rational” interpretation of the image data consistent with the given assumptions. This approach can easily be extended and generalized in a number of ways\, allowing a number of traditional problems in perceptual organization to be “probabilized.” I will briefly illustrate several such extensions\, including (1) figure/ground and grouping (3) 3D shape and (2) shape similarity.\n\n\n3:30 – 4:00pm\nTea Break\n\n\n\n4:00 – 4:45pm\nMoira Dillon\nTitle: Euclid’s Random Walk: Simulation as a tool for geometric reasoning through development \nAbstract: Formal geometry lies at the foundation of millennia of human achievement in domains such as mathematics\, science\, and art. While formal geometry’s propositions rely on abstract entities like dimensionless points and infinitely long lines\, the points and lines of our everyday world all have dimension and are finite. How\, then\, do we get to abstract geometric thought? In this talk\, I will provide evidence that evolutionarily ancient and developmentally precocious sensitivities to the geometry of our everyday world form the foundation of\, but also limit\, our mathematical reasoning. I will also suggest that successful geometric reasoning may emerge through development when children abandon incorrect\, axiomatic-based strategies and come to rely on dynamic simulations of physical entities. While problems in geometry may seem answerable by immediate inference or by deductive proof\, human geometric reasoning may instead rely on noisy\, dynamic simulations.\n\n\n4:45 – 5:30pm\nMichael McCloskey\nTitle: Axes and Coordinate Systems in Representing Object Shape and Orientation \nAbstract: I describe a theoretical perspective in which a) object shape is represented in an object-centered reference frame constructed around orthogonal axes; and b) object orientation is represented by mapping the object-centered frame onto an extrinsic (egocentric or environment-centered) frame.  I first show that this perspective is motivated by\, and sheds light on\, object orientation errors observed in neurotypical children and adults\, and in a remarkable case of impaired orientation perception. I then suggest that orientation errors can be used to address questions concerning how object axes are defined on the basis of object geometry—for example\, what aspects of object geometry (e.g.\, elongation\, symmetry\, structural centrality of parts) play a role in defining an object principal axis?\n\n\n5:30 – 6:30pm\nReception\n\n\n\n\n \nTuesday\, April 16 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 9:45am\nPeter Olver\nTitle: Symmetry and invariance in cognition — a mathematical perspective” \nAbstract: Symmetry recognition and appreciation is fundamental in human cognition.  (It is worth speculating as to why this may be so\, but that is not my intent.) The goal of these two talks is to survey old and new mathematical perspectives on symmetry and invariance.  Applications will arise from art\, computer vision\, geometry\, and beyond\, and will include recent work on 2D and 3D jigsaw puzzle assembly and an ongoing collaboration with anthropologists on the analysis and refitting of broken bones.  Mathematical pre\n\n\n9:45 – 10:30am\nStefano Soatto/Alessandro Achille\nTitle: Information in the Weights and Emergent Properties of Deep Neural Networks \nAbstract: We introduce the notion of information contained in the weights of a Deep Neural Network  and show that it can be used to control and describe the training process of DNNs\, and can explain how properties\, such as invariance to nuisance variability and disentanglement\, emerge naturally in the learned representation. Through its dynamics\, stochastic gradient descent (SGD) implicitly regularizes the information in the weights\, which can then be used to bound the generalization error through the PAC-Bayes bound. Moreover\, the information in the weights can be used to defined both a topology and an asymmetric distance in the space of tasks\, which can then be used to predict the training time and the performance on a new task given a solution to a pre-training task. \nWhile this information distance models difficulty of transfer in first approximation\, we show the existence of non-trivial irreversible dynamics during the initial transient phase of convergence when the network is acquiring information\, which makes the approximation fail. This is closely related to critical learning periods in biology\, and suggests that studying the initial convergence transient can yield important insight beyond those that can be gleaned from the well-studied asymptotics.\n\n\n10:30 – 11:00am\nCoffee Break\n\n\n\n11:00 – 11:45am\nJeannette Bohg\nTitle: On perceptual representations and how they interact with actions and physical representations \nAbstract: I will discuss the hypothesis that perception is active and shaped by our task and our expectations on how the world behaves upon physical interaction. Recent approaches in robotics follow this insight that perception is facilitated by physical interaction with the environment. First\, interaction creates a rich sensory signal that would otherwise not be present. And second\, knowledge of the regularity in the combined space of sensory data and action parameters facilitate the prediction and interpretation of the signal. In this talk\, I will present two examples from our previous work where a predictive task facilitates autonomous robot manipulation by biasing the representation of the raw sensory data. I will present results on visual but also haptic data.\n\n\n11:45 – 12:30pm\nDagmar Sternad\nTitle: Exploiting the Geometry of the Solution Space to Reduce Sensitivity to Neuromotor Noise \nAbstract: Control and coordination of skilled action is frequently examined in isolation as a neuromuscular problem. However\, goal-directed actions are guided by information that creates solutions that are defined as a relation between the actor and the environment. We have developed a task-dynamic approach that starts with a physical model of the task and mathematical analysis of the solution spaces for the task. Based on this analysis we can trace how humans develop strategies that meet complex demands by exploiting the geometry of the solution space. Using three interactive tasks – throwing or bouncing a ball and transporting a “cup of coffee” – we show that humans develop skill by: 1) finding noise-tolerant strategies and channeling noise into task-irrelevant dimensions\, 2) exploiting solutions with dynamic stability\, and 3) optimizing predictability of the object dynamics. These findings are the basis for developing propositions about the controller: complex actions are generated with dynamic primitives\, attractors with few invariant types that overcome substantial delays and noise in the neuro-mechanical system.\n\n\n12:30 – 2:00pm\nLunch\n\n\n\n2:00 – 2:45pm\nSam Ocko\nTitle: Emergent Elasticity in the Neural Code for Space \nAbstract: To navigate a novel environment\, animals must construct an internal map of space by combining information from two distinct sources: self-motion cues and sensory perception of landmarks. How do known aspects of neural circuit dynamics and synaptic plasticity conspire to construct such internal maps\, and how are these maps used to maintain representations of an animal’s position within an environment. We demonstrate analytically how a neural attractor model that combines path integration of self-motion with Hebbian plasticity in synaptic weights from landmark cells can self-organize a consistent internal map of space as the animal explores an environment. Intriguingly\, the emergence of this map can be understood as an elastic relaxation process between landmark cells mediated by the attractor network during exploration. Moreover\, we verify several experimentally testable predictions of our model\, including: (1) systematic deformations of grid cells in irregular environments\, (2) path-dependent shifts in grid cells towards the most recently encountered landmark\, (3) a dynamical phase transition in which grid cells can break free of landmarks in altered virtual reality environments and (4) the creation of topological defects in grid cells. Taken together\, our results conceptually link known biophysical aspects of neurons and synapses to an emergent solution of a fundamental computational problem in navigation\, while providing a unified account of disparate experimental observations.\n\n\n2:45 – 3:30pm\nTatyana Sharpee\nTitle: Hyperbolic geometry of the olfactory space \nAbstract: The sense of smell can be used to avoid poisons or estimate a food’s nutrition content because biochemical reactions create many by-products. Thus\, the production of a specific poison by a plant or bacteria will be accompanied by the emission of certain sets of volatile compounds. An animal can therefore judge the presence of poisons in the food by how the food smells. This perspective suggests that the nervous system can classify odors based on statistics of their co-occurrence within natural mixtures rather than from the chemical structures of the ligands themselves. We show that this statistical perspective makes it possible to map odors to points in a hyperbolic space. Hyperbolic coordinates have a long but often underappreciated history of relevance to biology. For example\, these coordinates approximate distance between species computed along dendrograms\, and more generally between points within hierarchical tree-like networks. We find that both natural odors and human perceptual descriptions of smells can be described using a three-dimensional hyperbolic space. This match in geometries can avoid distortions that would otherwise arise when mapping odors to perception. We identify three axes in the perceptual space that are aligned with odor pleasantness\, its molecular boiling point and acidity. Because the perceptual space is curved\, one can predict odor pleasantness by knowing the coordinates along the molecular boiling point and acidity axes.\n\n\n3:30 – 4:00pm\nTea Break\n\n\n\n4:00 – 4:45pm\nEd Connor\nTitle: Representation of solid geometry in object vision cortex \nAbstract: There is a fundamental tension in object vision between the 2D nature of retinal images and the 3D nature of physical reality. Studies of object processing in the ventral pathway of primate visual cortex have focused mainly on 2D image information. Our latest results\, however\, show that representations of 3D geometry predominate even in V4\, the first object-specific stage in the ventral pathway. The majority of V4 neurons exhibit strong responses and clear selectivity for solid\, 3D shape fragments. These responses are remarkably invariant across radically different image cues for 3D shape: shading\, specularity\, reflection\, refraction\, and binocular disparity (stereopsis). In V4 and in subsequent stages of the ventral pathway\, solid shape geometry is represented in terms of surface fragments and medial axis fragments. Whole objects are represented by ensembles of neurons signaling the shapes and relative positions of their constituent parts. The neural tuning dimensionality of these representations includes principal surface curvatures and their orientations\, surface normal orientation\, medial axis orientation\, axial curvature\, axial topology\, and position relative to object center of mass. Thus\, the ventral pathway implements a rapid transformation of 2D image data into explicit representations 3D geometry\, providing cognitive access to the detailed structure of physical reality.\n\n\n4:45 – 5:30pm\nL. Mahadevan\nTitle: Simple aspects of geometry and probability in perception \nAbstract: Inspired by problems associated with noisy perception\, I will discuss two questions: (i) how might we test people’s perception of probability in a geometric context ? (ii) can one construct invariant descriptions of 2D images using simple notions of probabilistic geometry? Along the way\, I will highlight other questions that the intertwining of geometry and probability raises in a broader perceptual context.\n\n\n\n\nWednesday\, April 17 \n\n\n\nTime\nSpeaker\nTitle/Abstract\n\n\n8:30 – 9:00am\nBreakfast\n\n\n\n9:00 – 9:45am\nGily Ginosar\nTitle: The 3D geometry of grid cells in flying bats \nAbstract: The medial entorhinal cortex (MEC) contains a variety of spatial cells\, including grid cells and border cells. In 2D\, grid cells fire when the animal passes near the vertices of a 2D spatial lattice (or grid)\, which is characterized by circular firing-fields separated by fixed distances\, and 60 local angles – resulting in a hexagonal structure. Although many animals navigate in 3D space\, no studies have examined the 3D volumetric firing of MEC neurons. Here we addressed this by training Egyptian fruit bats to fly in a large room (5.84.62.7m)\, while we wirelessly recorded single neurons in MEC. We found 3D border cells and 3D head-direction cells\, as well as many neurons with multiple spherical firing-fields. 20% of the multi-field neurons were 3D grid cells\, exhibiting a narrow distribution of characteristic distances between neighboring fields – but not a perfect 3D global lattice. The 3D grid cells formed a functional continuum with less structured multi-field neurons. Both 3D grid cells and multi-field cells exhibited an anatomical gradient of spatial scale along the dorso-ventral axis of MEC\, with inter-field spacing increasing ventrally – similar to 2D grid cells in rodents. We modeled 3D grid cells and multi-field cells as emerging from pairwise-interactions between fields\, using an energy potential that induces repulsion at short distances and attraction at long distances. Our analysis shows that the model explains the data significantly better than a random arrangement of fields. Interestingly\, simulating the exact same model in 2D yielded a hexagonal-like structure\, akin to grid cells in rodents. Together\, the experimental data and preliminary modeling suggest that the global property of grid cells is multiple fields that repel each other with a characteristic distance-scale between adjacent fields – which in 2D yields a global hexagonal lattice while in 3D yields only local structure but no global lattice. \nGily Ginosar 1 \, Johnatan Aljadeff 2 \, Yoram Burak 3 \, Haim Sompolinsky 3 \, Liora Las 1 \, Nachum Ulanovsky 1 \n(1) Department of Neurobiology\, Weizmann Institute of Science\, Rehovot 76100\, Israel \n(2) Department of Bioengineering\, Imperial College London\, London\, SW7 2AZ\, UK \n(3) The Edmond and Lily Safra Center for Brain Sciences\, and Racah Institute of Physics\, The Hebrew \nUniversity of Jerusalem\, Jerusalem\, 91904\, Israel\n\n\n9:45 – 10:30am\nSandro Romani\nTitle: Neural networks for 3D rotations \nAbstract: Studies in rodents\, bats\, and humans have uncovered the existence of neurons that encode the orientation of the head in 3D. Classical theories of the head-direction (HD) system in 2D rely on continuous attractor neural networks\, where neurons with similar heading preference excite each other\, while inhibiting other HD neurons. Local excitation and long-range inhibition promote the formation of a stable “bump” of activity that maintains a representation of heading. The extension of HD models to 3D is hindered by complications (i) 3D rotations are non-commutative (ii) the space described by all possible rotations of an object has a non-trivial topology. This topology is not captured by standard parametrizations such as Euler angles (e.g. yaw\, pitch\, roll). For instance\, with these parametrizations\, a small change of the orientation of the head could result in a dramatic change of neural representation. We used methods from the representation theory of groups to develop neural network models that exhibit patterns of persistent activity of neurons mapped continuously to the group of 3D rotations. I will further discuss how these networks can (i) integrate vestibular inputs to update the representation of heading\, and (ii) be used to interpret “mental rotation” experiments in humans. \nThis is joint work with Hervé Rouault (CENTURI) and Alon Rubin (Weizmann Institute of Science).\n\n\n10:30 – 11:00am\nCoffee Break\n\n\n\n11:00 – 11:45am\nSam Gershman\nTitle: The hippocampus as a predictive map \nAbstract: A cognitive map has long been the dominant metaphor for hippocampal function\, embracing the idea that place cells encode a geometric representation of space. However\, evidence for predictive coding\, reward sensitivity and policy dependence in place cells suggests that the representation is not purely spatial. I approach this puzzle from a reinforcement learning perspective: what kind of spatial representation is most useful for maximizing future reward? I show that the answer takes the form of a predictive representation. This representation captures many aspects of place cell responses that fall outside the traditional view of a cognitive map. Furthermore\, I argue that entorhinal grid cells encode a low-dimensionality basis set for the predictive representation\, useful for suppressing noise in predictions and extracting multiscale structure for hierarchical planning.\n\n\n11:45 – 12:30pm\nLucia Jacobs\nTitle: The adaptive geometry of a chemosensor: the origin and function of the vertebrate nose \nAbstract: A defining feature of a living organism\, from prokaryotes to plants and animals\, is the ability to orient to chemicals. The distribution of chemicals\, whether in water\, air or on land\, is used by organisms to locate and exploit spatially distributed resources\, such as nutrients and reproductive partners. In animals\, the evolution of a nervous system coincided with the evolution of paired chemosensors. In contemporary insects\, crustaceans\, mollusks and vertebrates\, including humans\, paired chemosensors confer a stereo olfaction advantage on the animal’s ability to orient in space. Among vertebrates\, however\, this function faced a new challenge with the invasion of land. Locomotion on land created a new conflict between respiration and spatial olfaction in vertebrates. The need to resolve this conflict could explain the current diversity of vertebrate nose geometries\, which could have arisen due to species differences in the demand for stereo olfaction. I will examine this idea in more detail in the order Primates\, focusing on Old World primates\, in particular\, the evolution of an external nose in the genus Homo.\n\n\n12:30 – 1:30pm\nLunch\n\n\n\n1:30 – 2:15pm\nTalia Konkle\nTitle: The shape of things and the organization of object-selective cortex \nAbstract: When we look at the world\, we effortlessly recognize the objects around us and can bring to mind a wealth of knowledge about their properties. In part 1\, I’ll present evidence that neural responses to objects are organized by high-level dimensions of animacy and size\, but with underlying neural tuning to mid-level shape features. In part 2\, I’ll present evidence that representational structure across much of the visual system has the requisite structure to predict visual behavior. Together\, these projects suggest that there is a ubiquitous “shape space” mapped across all of occipitotemporal cortex that underlies our visual object processing capacities. Based on these findings\, I’ll speculate that the large-scale spatial topography of these neural responses is critical for pulling explicit content out of a representational geometry.\n\n\n2:15 – 3:00pm\nVijay Balasubramanian\nTitle: Becoming what you smell: adaptive sensing in the olfactory system \nAbstract: I will argue that the circuit architecture of the early olfactory system provides an adaptive\, efficient mechanism for compressing the vast space of odor mixtures into the responses of a small number of sensors.  In this view\, the olfactory sensory repertoire employs a disordered code to compress a high dimensional olfactory space into a low dimensional receptor response space while preserving distance relations between odors.  The resulting representation is dynamically adapted to efficiently encode the changing environment of volatile molecules.  I will show that this adaptive combinatorial code can be efficiently decoded by systematically eliminating candidate odorants that bind to silent receptors.  The resulting algorithm for “estimation by elimination” can be implemented by a neural network that is remarkably similar to the early olfactory pathway in the brain.  The theory predicts a relation between the diversity of olfactory receptors and the sparsity of their responses that matches animals from flies to humans.   It also predicts specific deficits in olfactory behavior that should result from optogenetic manipulation of the olfactory bulb.\n\n\n3:00 – 3:45pm\nIla Feite\nTitle: Invariance\, stability\, geometry\, and flexibility in spatial navigation circuits \nAbstract: I will describe how the geometric invariances or symmetries of the external world are reflected in the symmetries of neural circuits that represent it\, using the example of the brain’s networks for spatial navigation. I will discuss how these symmetries enable spatial memory\, evidence integration\, and robust representation. At the same time\, I will discuss how these seemingly rigid circuits with their inscribed symmetries can be harnessed to represent a range of spatial and non-spatial cognitive variables with high flexibility.\n\n\n3:45 – 4:00pm\nL Mahadevan – summary
URL:https://cmsa.fas.harvard.edu/event/workshop-on-invariance-and-geometry-in-sensation-action-and-cognition/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190410T143000
DTEND;TZID=America/New_York:20190410T153000
DTSTAMP:20260508T100604
CREATED:20240212T112326Z
LAST-MODIFIED:20240514T181503Z
UID:10002069-1554906600-1554910200@cmsa.fas.harvard.edu
SUMMARY:Inequality Aversion\, Populism\, and the Backlash Against Globalization
DESCRIPTION:Speaker: Pietro Veronesi (University of Chicago) \nTitle: Inequality Aversion\, Populism\, and the Backlash Against Globalization \nAbstract: Motivated by the recent rise of populism in western democracies\, we develop a model in which a populist backlash emerges endogenously in a growing economy. In the model\, voters dislike inequality\, especially the high consumption of “elites.” Economic growth exacerbates inequality due to heterogeneity in risk aversion. In response to rising inequality\, rich-country voters optimally elect a populist promising to end globalization. Countries with more inequality\, higher financial development\, and current account deficits are more vulnerable to populism\, both in the model and in the data. Evidence on who voted for Brexit and Trump in 2016 also supports the model.
URL:https://cmsa.fas.harvard.edu/event/4-10-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-041019-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190403T143000
DTEND;TZID=America/New_York:20190403T153000
DTSTAMP:20260508T100604
CREATED:20240212T112705Z
LAST-MODIFIED:20240514T181644Z
UID:10002077-1554301800-1554305400@cmsa.fas.harvard.edu
SUMMARY:Deregulation through Direct Democracy: Lessons from Liquor
DESCRIPTION:Speaker:  Sarah Moshary (University of Chicago) \nTitle:  Deregulation through Direct Democracy: Lessons from Liquor \nAbstract:  This paper examines the merits of state control versus private provision of spirits retail\, using the 2012 deregulation of liquor sales in Washington state as an event study. We document effects along a number of dimensions: prices\, product variety\, convenience\, substitution to other goods\, state revenue\, and consumption externalities. We estimate a demand system to evaluate the net effect of privatization on consumer welfare. Our findings suggest that deregulation harmed the median Washingtonian\, even though residents voted in favor of deregulation by a 16% margin. Further\, we find that vote shares for the deregulation initiative do not reflect welfare gains at the ZIP code level. We discuss implications of our findings for the efficacy of direct democracy as a policy tool.
URL:https://cmsa.fas.harvard.edu/event/4-3-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-040319.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190327T171500
DTEND;TZID=America/New_York:20190327T181500
DTSTAMP:20260508T100604
CREATED:20240212T110407Z
LAST-MODIFIED:20240514T181829Z
UID:10002031-1553706900-1553710500@cmsa.fas.harvard.edu
SUMMARY:Hyperbolic geometry of the olfactory space
DESCRIPTION:Speaker: Tatyana Sharpee (Salk Institute for Biological Studies) \nTitle: Hyperbolic geometry of the olfactory space \nAbstract: The sense of smell can be used to avoid poisons or estimate a food’s nutrition content because biochemical reactions create many by-products. Thus\, the presence of certain bacteria in the food becomes associated with the emission of certain volatile compounds. This perspective suggests that it would be convenient for the nervous system encode odors based on statistics of their co-occurrence within natural mixtures rather than based on the chemical structure per se. I will discuss how this statistical perspective makes it possible to map odors to points in a hyperbolic space. Hyperbolic coordinates have a long but often underappreciated history of relevance to biology. For example\, these coordinates approximate distance between species computed along dendograms\, and more generally between points within hierarchical tree-like networks. We find that these coordinates\, which were generated purely based on the statistics of odors in the natural environment\, provide a contiguous map of human odor pleasantness. Further\, a separate analysis of human perceptual descriptions of smells indicates that these also generate a three dimensional hyperbolic representation of odors. This match in geometries between natural odor statistics and human perception can help to minimize distortions that would otherwise arise when mapping odors to perception. We identify three axes in the perceptual space that are aligned with odor pleasantness\, its molecular boiling point and acidity. Because the perceptual space is curved\, one can predict odor pleasantness by knowing the coordinates along the molecular boiling point and acidity axes. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/3-27-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-032719.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190320T163000
DTEND;TZID=America/New_York:20190320T173000
DTSTAMP:20260508T100604
CREATED:20240212T105115Z
LAST-MODIFIED:20240507T204308Z
UID:10002015-1553099400-1553103000@cmsa.fas.harvard.edu
SUMMARY:Quality Externalities on Platforms: The Case of Airbnb
DESCRIPTION:Speaker:  Sonia Jaffe  (Microsoft) \nTitle: Quality Externalities on Platforms: The Case of Airbnb \nAbstract:  We explore quality externalities on platforms: when buyers have limited information\, a seller’s quality affects whether her buyers return to the platform\, thereby impacting other sellers’ future business. We propose an intuitive measure of this externality\, applicable across a range of platforms. Guest Return Propensity (GRP) is the aggregate propensity of a seller’s customers to return to the platform. We validate this metric using Airbnb data: matching customers to listings with a one standard deviation higher GRP causes them to take 17% more subsequent trips. By directing buyers to higher-GRP sellers\, platforms may be able to increase overall seller surplus. (Joint work with Peter Coles\, Steven Levitt\, and Igor Popov.)
URL:https://cmsa.fas.harvard.edu/event/3-20-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=application/pdf:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-032019.pdf
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190318T090000
DTEND;TZID=America/New_York:20190320T170000
DTSTAMP:20260508T100604
CREATED:20230715T091111Z
LAST-MODIFIED:20250304T213630Z
UID:10000109-1552899600-1553101200@cmsa.fas.harvard.edu
SUMMARY:Workshop on Mirror Symmetry and Stability
DESCRIPTION:This three-day workshop will take place at Harvard University on March 18-20\, 2019 in Science Center room 507. The main topic will be stability conditions in homological mirror symmetry. This workshop is funded by the Simons Collaboration in Homological Mirror Symmetry. \nOrganizers: Denis Auroux\, Yu-Wei Fan\, Hansol Hong\, Siu-Cheong Lau\, Bong Lian\, Shing-Tung Yau\, Jingyu Zhao \nSpeakers: \nDylan Allegretti (Sheffield)\nTristan Collins (MIT)\nNaoki Koseki (Tokyo)\nChunyi Li (Warwick)\nJason Lo (CSU Northridge)\nEmanuele Macrì (NEU & IHES)\nGenki Ouchi (Riken iTHEMS)\nPranav Pandit (ICTS)\nLaura Pertusi (Edinburgh)\nJacopo Stoppa (SISSA)\nAlex Takeda (UC Berkeley)\nXiaolei Zhao (UC Santa Barbara) \nMore details will be added later. \nVisit the event page for more information.  \n  \n 
URL:https://cmsa.fas.harvard.edu/event/workshop-on-mirror-symmetry-and-stability/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/HMS-2019-1-768x994-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190313T171500
DTEND;TZID=America/New_York:20190313T181500
DTSTAMP:20260508T100604
CREATED:20240212T105402Z
LAST-MODIFIED:20240514T182140Z
UID:10002017-1552497300-1552500900@cmsa.fas.harvard.edu
SUMMARY:On the geometry and topology of initial data sets in General Relativity
DESCRIPTION:Speaker: Greg Galloway (University of Miami) \nTitle: On the geometry and topology of initial data sets in General Relativity \nAbstract: A theme of long standing interest (to the speaker!) concerns the relationship between the topology of spacetime and the occurrence of singularities (causal geodesic incompleteness). Many results concerning this center around the notion of topological censorship\, which has to do with the idea that the region outside all black holes (and white holes) should be simple. The aim of the results to be presented is to provide support for topological censorship at the pure initial data level\, thereby circumventing difficult issues of global evolution. The proofs rely on the recently developed theory of marginally outer trapped surfaces\, which are natural spacetime analogues of minimal surfaces in Riemannian geometry. The talk will begin with a brief overview of general relativity and topological censorship. The talk is based primarily on joint work with various collaborators: Lars Andersson\, Mattias Dahl\, Michael Eichmair and Dan Pollack.
URL:https://cmsa.fas.harvard.edu/event/2-13-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-031319-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190313T090000
DTEND;TZID=America/New_York:20190315T170000
DTSTAMP:20260508T100604
CREATED:20230717T174351Z
LAST-MODIFIED:20250305T192752Z
UID:10000046-1552467600-1552669200@cmsa.fas.harvard.edu
SUMMARY:Fluid turbulence and Singularities of the Euler/ Navier Stokes equations
DESCRIPTION:The Workshop on Fluid turbulence and Singularities of the Euler/ Navier Stokes equations will take place on March 13-15\, 2019. This is the first of two workshop organized by Michael Brenner\, Shmuel Rubinstein\, and Tom Hou. The second\, Machine Learning for Multiscale Model Reduction\, will take place on March 27-29\, 2019. Both workshops will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. \n  \nSpeakers: \n\nClaude Bardos\, University of Paris\nJiajie Chen\, Caltech\nPeter Constantin\, Princeton\nDiego Cordoba\, ICMAT\nTarek Elgindi\, UCSD\nSusumu Goto\, Osaka\nAlexander Kiselev\, Duke University\nAlain Pumir\, ENS Lyon\nShmuel Rubinstein\, Harvard SEAS\nVladimir Sverak\, University of Minnesota\nEdriss S. Titi\, TAMU\nVlad Vicol\, Courant\nSijue Wu\, University of Michigan\nAndrej Zlatos\, UCSD
URL:https://cmsa.fas.harvard.edu/event/fluid-turbulence-and-singularities-of-the-euler-navier-stokes-equations/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Fluid-Turbulence-Poster-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190228T143000
DTEND;TZID=America/New_York:20190228T150000
DTSTAMP:20260508T100604
CREATED:20240212T104226Z
LAST-MODIFIED:20240514T182343Z
UID:10002002-1551364200-1551366000@cmsa.fas.harvard.edu
SUMMARY:A sharp transition for Gibbs measures associated to the nonlinear Schrödinger equation
DESCRIPTION:Speaker: Philippe Sosoe (Cornell) \nTitle: A sharp transition for Gibbs measures associated to the nonlinear Schrödinger equation \nAbstract: In 1987\, Lebowitz\, Rose and Speer (LRS) showed how to construct formally invariant measures for the nonlinear Schrödinger equation on the torus. This seminal contribution spurred a large amount of activity in the area of partial differential equations with random initial data. In this talk\, I will explain LRS’s result\, and discuss a sharp transition in the construction of the Gibbs-type invariant measures considered by these authors. (Joint work with Tadahiro Oh and Leonardo Tolomeo)
URL:https://cmsa.fas.harvard.edu/event/3-6-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-030619-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190227T143000
DTEND;TZID=America/New_York:20190227T153000
DTSTAMP:20260508T100604
CREATED:20240212T102330Z
LAST-MODIFIED:20240514T182606Z
UID:10001978-1551277800-1551281400@cmsa.fas.harvard.edu
SUMMARY:Sentiment and Speculation in a Market with Heterogeneous Beliefs
DESCRIPTION:Speaker: Ian Martin (LSE) \nTitle: Sentiment and Speculation in a Market with Heterogeneous Beliefs \nAbstract: We present a dynamic model featuring risk-averse investors with heterogeneous beliefs. Individual investors have stable beliefs and risk aversion\, but agents who were correct in hindsight become relatively wealthy; their beliefs are overrepresented in market sentiment\, so “the market” is bullish following good news and bearish following bad news. Extreme states are far more important than in a homogeneous economy. Investors understand that sentiment drives volatility up\, and demand high risk premia in compensation. Moderate investors supply liquidity: they trade against market sentiment in the hope of capturing a variance risk premium created by the presence of extremists. [Joint work with Dimitris Papadimitriou] \n  \n 
URL:https://cmsa.fas.harvard.edu/event/2-27-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-022719-e1550767365109.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190225T093000
DTEND;TZID=America/New_York:20190301T170000
DTSTAMP:20260508T100604
CREATED:20230715T090551Z
LAST-MODIFIED:20240209T214453Z
UID:10000108-1551087000-1551459600@cmsa.fas.harvard.edu
SUMMARY:Growth and zero sets of eigenfunctions and of solutions to elliptic partial differential equations
DESCRIPTION:From February 25 to March 1\, the CMSA will be hosting a workshop on Growth and zero sets of eigenfunctions and of solutions to elliptic partial differential equations.  \nKey participants of this workshop include David Jerison (MIT)\, Alexander Logunov (IAS)\, and Eugenia Malinnikova (IAS).  This workshop will have morning sessions on Monday-Friday of this week from 9:30-11:30am\, and afternoon sessions on Monday\, Tuesday\, and Thursday from 3:00-5:00pm.\nThe sessions will be held in  \(G02\) (downstairs) at 20 Garden\, except for Tuesday afternoon\, when the talk will be in \(G10\).
URL:https://cmsa.fas.harvard.edu/event/growth-and-zero-sets-of-eigenfunctions-and-of-solutions-to-elliptic-partial-differential-equations/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190220T163000
DTEND;TZID=America/New_York:20190220T173000
DTSTAMP:20260508T100604
CREATED:20240212T114533Z
LAST-MODIFIED:20240514T182813Z
UID:10002102-1550680200-1550683800@cmsa.fas.harvard.edu
SUMMARY:Optimally Imprecise Memory and Biased Forecasts
DESCRIPTION:Speaker: Michael Woodford (Columbia) \nTitle: Optimally Imprecise Memory and Biased Forecasts \nAbstract: We propose a model of optimal decision making subject to a memory constraint. The constraint is a limit on the complexity of memory measured using Shannon’s mutual information\, as in models of rational inattention; the structure of the imprecise memory is optimized (for a given decision problem and noisy environment) subject to this constraint. We characterize the form of the optimally imprecise memory\, and show that the model implies that both forecasts and actions will exhibit idiosyncratic random variation; that beliefs will fluctuate forever around the rational-expectations (perfect-memory) beliefs with a variance that does not fall to zero; and that more recent news will be given disproportionate weight. The model provides a simple explanation for a number of features of observed forecast bias in laboratory and field settings. [Joint work with Rava Azeredo da Silveira and Yeji Sung
URL:https://cmsa.fas.harvard.edu/event/2-20-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-022019-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190207T163000
DTEND;TZID=America/New_York:20190207T173000
DTSTAMP:20260508T100604
CREATED:20240212T101329Z
LAST-MODIFIED:20240514T182948Z
UID:10001963-1549557000-1549560600@cmsa.fas.harvard.edu
SUMMARY:Inference for the Mean
DESCRIPTION:Speaker: Ulrich Mueller (Princeton) \nTitle: Inference for the Mean \nAbstract: Consider inference about the mean of a population with finite variance\, based on an i.i.d. sample. The usual t-statistic yields correct inference in large samples\, but heavy tails induce poor small sample behavior. This paper combines extreme value theory for the smallest and largest observations with a normal approximation for the t-statistic of a truncated sample to obtain more accurate inference. This alternative approximation is shown to provide a refinement over the standard normal approximation to the full sample t-statistic under more than two but less than three moments\, while the bootstrap does not. Small sample simulations suggest substantial size improvements over the bootstrap.
URL:https://cmsa.fas.harvard.edu/event/2-7-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-020719.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190119T163000
DTEND;TZID=America/New_York:20190119T163000
DTSTAMP:20260508T100604
CREATED:20240212T100703Z
LAST-MODIFIED:20240514T183205Z
UID:10001956-1547915400-1547915400@cmsa.fas.harvard.edu
SUMMARY:Innovation in Cell Phones in the US and China: Who Improves Technology Faster?
DESCRIPTION:Speaker: Richard B. Freeman (Harvard University and NBER) \nTitle: Innovation in Cell Phones in the US and China: Who Improves Technology Faster? \nAbstract: Cell phones are the archetypical modern consumer innovation\, spreading around the world at an incredible pace\, extensively used for connecting people with the Internet and diverse apps. Consumers report spending from 2-5 hours a day at their cell phones\, with 44% of Americans saying “couldn’t go a day without their mobile devices.” Cell phone manufacturers introduce new models regularly\, embodying additional features while other firms produce new applications that increase demand for the phones. Using newly developed data on the prices\, attributes\, and sales of different models in the US and China\, this paper estimates the magnitude of technological change in the phones in the 2000s. It explores the problems of analyzing a product with many interactive attributes in the standard hedonic price regression model and uses Principal Components Regression to reduce dimensionality. The main finding is that technology improved the value of cell phones at comparable rates in the US and China\, despite different market structures and different evaluations of some attributes and brands. The study concludes with a discussion of ways to evaluate the economic surplus created by the cell phones and their contribution to economic well-being.
URL:https://cmsa.fas.harvard.edu/event/1-30-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Screen-Shot-2019-01-29-at-9.16.13-AM.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190118T083000
DTEND;TZID=America/New_York:20190121T173000
DTSTAMP:20260508T100604
CREATED:20230715T090318Z
LAST-MODIFIED:20241212T192232Z
UID:10000105-1547800200-1548091800@cmsa.fas.harvard.edu
SUMMARY:Geometric Analysis Approach to AI Workshop
DESCRIPTION:Due to inclement weather on Sunday\, the second half of the workshop has been moved forward one day. Sunday and Monday’s talks will now take place on Monday and Tuesday.\nOn January 18-21\, 2019 the Center of Mathematical Sciences and Applications will be hosting a workshop on the Geometric Analysis Approach to AI. \nThis workshop will focus on the theoretic foundations of AI\, especially various methods in Deep Learning. The topics will cover the relationship between deep learning and optimal transportation theory\, DL and information geometry\, DL Learning and information bottle neck and renormalization theory\, DL and manifold embedding and so on. Furthermore\, the recent advancements\, novel methods\, and real world applications of Deep Learning will also be reported and discussed. \nThe workshop will take place from January 18th to January 23rd\, 2019. In the first four days\, from January 18th to January 21\, the speakers will give short courses; On the 22nd and 23rd\, the speakers will give conference representations. This workshop is organized by Xianfeng Gu and Shing-Tung Yau. \nThe workshop will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA.  \nSpeakers:  \n\nSarah Adel Bargal\, Boston University\nGuy Bresler\, MIT\nTina Eliassi-Rad\, Northeastern\nYun Raymond Fu\, Northeastern\nBrian Kulis\, Boston University\nNa Lei\, Dalian University of Technology\nYi Ma\, UC Berkeley\nMinh Hoai Nguyen\, Stony Brook\nFrancesco Orabona\, Boston University\nCengiz Pehlevan\, Harvard SEAS\nTomaso Poggio\, MIT\nZhiwei Qin\, DiDi Research America\nKate Saenko\, Boston University\nDimitris Samaras\, Stony Brook\nJohannes Schmidt-Hieber\, University of Twente\nSteven Skiena\, Stony Brook\nVivienne Sze\, MIT\nNaftali Tishby\, ICNC\nJiajun Wu\, MIT\nYing Nian Wu\, UCLA\nGangqiang Xia\, Morgan Stanley\nEric Xing\, Carnegie Mellon\nDonghui Yan\, UMass Dartmouth\nAlan Yuille\, Johns Hopkins\nJuhua Zhu\,  Argus
URL:https://cmsa.fas.harvard.edu/event/geometric-analysis-approach-to-ai-workshop/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Geo-Analysis-Poster-final-e1547584167900.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181205T163000
DTEND;TZID=America/New_York:20181205T173000
DTSTAMP:20260508T100604
CREATED:20240213T072513Z
LAST-MODIFIED:20240514T183912Z
UID:10002179-1544027400-1544031000@cmsa.fas.harvard.edu
SUMMARY:Displacement convexity of Boltzmann's entropy characterizes positive energy in general relativity
DESCRIPTION:Speaker: Robert McCann (University of Toronto) \nTitle: Displacement convexity of Boltzmann’s entropy characterizes positive energy in general relativity \nAbstract: Einstein’s theory of gravity is based on assuming that the fluxes of a energy and momentum in a physical system are proportional to a certain variant of the Ricci curvature tensor on a smooth 3+1 dimensional spacetime. The fact that gravity is attractive rather than repulsive is encoded in the positivity properties which this tensor is assumed to satisfy.  Hawking and Penrose (1971) used this positivity of energy to give conditions under which smooth spacetimes must develop singularities. By lifting fractional powers of the Lorentz distance between points on a globally hyperbolic spacetime to probability measures on spacetime events\, we show that the strong energy condition of Hawking and Penrose is equivalent to convexity of the Boltzmann-Shannon entropy along the resulting geodesics of probability measures. This new characterization of the strong energy condition on globally hyperbolic manifolds also makes sense in (non-smooth) metric measure settings\, where it has the potential to provide a framework for developing a theory of gravity which admits certain singularities and can be continued beyond them. It provides a Lorentzian analog of Lott\, Villani and Sturm’s metric-measure theory of lower Ricci bounds\, and hints at new connections linking gravity to the second law of thermodynamics. Preprint available at http://www.math.toronto.edu/mccann/papers/GRO.pdf \n 
URL:https://cmsa.fas.harvard.edu/event/12-05-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-120518.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181203T083000
DTEND;TZID=America/New_York:20181205T143000
DTSTAMP:20260508T100604
CREATED:20230715T090021Z
LAST-MODIFIED:20250305T212541Z
UID:10000103-1543825800-1544020200@cmsa.fas.harvard.edu
SUMMARY:Morphogenesis: Geometry and Physics
DESCRIPTION:Just over a century ago\, the biologist\, mathematician and philologist D’Arcy Thompson wrote “On growth and form”. The book – a literary masterpiece – is a visionary synthesis of the geometric biology of form. It also served as a call for mathematical and physical approaches to understanding the evolution and development of shape. In the century since its publication\, we have seen a revolution in biology following the discovery of the genetic code\, which has uncovered the molecular and cellular basis for life\, combined with the ability to probe the chemical\, structural\, and dynamical nature of molecules\, cells\, tissues and organs across scales. In parallel\, we have seen a blossoming of our understanding of spatiotemporal patterning in physical systems\, and a gradual unveiling of the complexity of physical form. So\, how far are we from realizing the century-old vision that “Cell and tissue\, shell and bone\, leaf and flower\, are so many portions of matter\, and it is in obedience to the laws of physics that their particles have been moved\, moulded and conformed ?” \nTo address this requires an appreciation of the enormous ‘morphospace’ in terms of the potential shapes and sizes that living forms take\, using the language of mathematics. In parallel\, we need to consider the biological processes that determine form in mathematical terms is based on understanding how instabilities and patterns in physical systems might be harnessed by evolution. \nIn Fall 2018\, CMSA will focus on a program that aims at recent mathematical advances in describing shape using geometry and statistics in a biological context\, while also considering a range of physical theories that can predict biological shape at scales ranging from macromolecular assemblies to whole organ systems.\nThe first workshop will focus on the interface between Morphometrics and Mathematics\, while the second will focus on the interface between Morphogenesis and Physics.The workshop is organized by L. Mahadevan (Harvard)\, O. Pourquie (Harvard)\, A. Srivastava (Florida). \nAs part of the program on Mathematical Biology a workshop on Morphogenesis: Geometry and Physics will take place on December 3-5\, 2018.  The workshop will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. \nVideos\nSpeakers:\n\nArkhat Abzhanov\, Imperial College\nYohanns Bellaiche\, Paris\nCheng Ming Chuong\, USC\nZev Gartner\, UCSF\nThomas Gregor\, Princeton\nDagmar Iber\, Zurich\nIan Jermyn\, Durham University\nRaymond Keller\, UVA\nAllon Klein\, HMS\nLisa Manning\, Syracuse\nCristina Marchetti\, UCSB\nSean Megason\, HMS\nElliot Meyerowitz\, Caltech\nMichel Milinkovitch\, Geneva\nLeonardo Morsut\, USC\nOlivier Pourquié\, HMS\nEric Siggia\, Rockefeller University\nBen Simons\, Cambridge\nSebastian Streichan\, UCSB\nAryeh Warmflash\, Rice
URL:https://cmsa.fas.harvard.edu/event/morphogenesis-geometry-and-physics/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Programs
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181128T163000
DTEND;TZID=America/New_York:20181128T173000
DTSTAMP:20260508T100604
CREATED:20240213T072819Z
LAST-MODIFIED:20240514T184301Z
UID:10002180-1543422600-1543426200@cmsa.fas.harvard.edu
SUMMARY:Recent progress on mean curvature flow
DESCRIPTION:Speaker: Robert Haslhofer (University of Toronto) \nTitle: Recent progress on mean curvature flow \nAbstract: A family of surfaces moves by mean curvature flow if the velocity at each point is given by the mean curvature vector. Mean curvature flow is the most natural evolution in extrinsic geometry and shares many features with Hamilton’s Ricci flow from intrinsic geometry. In the first half of the talk\, I will give an overview of the well developed theory in the mean convex case\, i.e. when the mean curvature vector everywhere on the surface points inwards. Mean convex mean curvature flow can be continued through all singularities either via surgery or as level set solution\, with a precise structure theory for the singular set. In the second half of the talk\, I will report on recent progress in the general case without any curvature assumptions. Namely\, I will describe our solution of the mean convex neighborhood conjecture and the nonfattening conjecture\, as well as a general classification result for all possible blowup limits near spherical or cylindrical singularities. In particular\, assuming Ilmanen’s multiplicity one conjecture\, we conclude that for embedded two-spheres the mean curvature flow through singularities is well-posed. This is joint work with Kyeongsu Choi and Or Hershkovits.
URL:https://cmsa.fas.harvard.edu/event/11-28-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-112818-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181119T150000
DTEND;TZID=America/New_York:20181119T160000
DTSTAMP:20260508T100604
CREATED:20240213T071141Z
LAST-MODIFIED:20240514T184752Z
UID:10002165-1542639600-1542643200@cmsa.fas.harvard.edu
SUMMARY:Computational Principles of Auditory Cortex
DESCRIPTION:Speaker: Xiaoqin Wang (Johns Hopkins University) \nTitle: Computational Principles of Auditory Cortex \nAbstract: Auditory cortex is located at the top of a hierarchical processing pathway in the brain that encodes acoustic information. This brain region is crucial for speech and music perception and vocal production. Auditory cortex has long been considered a difficult brain region to study and remained one of less understood sensory cortices. Studies have shown that neural computation in auditory cortex is highly nonlinear. In contrast to other sensory systems\, the auditory system has a longer pathway between sensory receptors and the cerebral cortex. This unique organization reflects the needs of the auditory system to process time-varying and spectrally overlapping acoustic signals entering the ears from all spatial directions at any given time. Unlike visual or somatosensory cortices\, auditory cortex must also process and differentiate sounds that are externally generated or self-produced (during speaking). Neural representations of acoustic information in auditory cortex are shaped by auditory feedback and vocal control signals during speaking. Our laboratory has developed a unique and highly vocal non-human primate model (the common marmoset) and quantitative tools to study neural mechanisms underlying audition and vocal communication.
URL:https://cmsa.fas.harvard.edu/event/11-19-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-111918.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181114T160000
DTEND;TZID=America/New_York:20181114T170000
DTSTAMP:20260508T100604
CREATED:20240213T071016Z
LAST-MODIFIED:20240514T184520Z
UID:10002163-1542211200-1542214800@cmsa.fas.harvard.edu
SUMMARY:The virtual fundamental class in symplectic geometry
DESCRIPTION:Speaker: Dusa McDuff (Columbia University)  \nTitle: The virtual fundamental class in symplectic geometry \nAbstract: Essential to many constructions and applications of symplectic geometry is the ability to count J-holomorphic curves. The moduli spaces of such curves have well understood compactifications\, and if cut out transversally are oriented manifolds of dimension equal to the index of the problem\, so that they a fundamental class that can be used to count curves. In the general case\, when the defining equation is not transverse\, there are various different approaches to constructing a representative for this class\, We will discuss and compare different approaches to such a construction e.g. using polyfolds or various kinds of finite dimensional reduction. Most of this is joint work with Katrin Wehrheim. \n 
URL:https://cmsa.fas.harvard.edu/event/11-14-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-111418.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181031T163000
DTEND;TZID=America/New_York:20181031T173000
DTSTAMP:20260508T100604
CREATED:20240213T072029Z
LAST-MODIFIED:20240514T184941Z
UID:10002176-1541003400-1541007000@cmsa.fas.harvard.edu
SUMMARY:Exploring the (massive) space of graph partitions
DESCRIPTION:Speaker: Moon Duchin (Tufts) \nTitle: Exploring the (massive) space of graph partitions \nAbstract: The problem of electoral redistricting can be set up as a search of the space of partitions of a graph (representing the units of a state or other jurisdiction) subject to constraints (state and federal rules about the properties of districts).  I’ll survey the problem and some approaches to studying it\, with an emphasis on the deep mathematical questions it raises\, from combinatorial enumeration to discrete differential geometry to dynamics. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/colloquium-10-31-2018/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/2018_10_29_11_55_54.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181022T090000
DTEND;TZID=America/New_York:20190417T170000
DTSTAMP:20260508T100604
CREATED:20230904T082647Z
LAST-MODIFIED:20240105T154957Z
UID:10000009-1540198800-1555520400@cmsa.fas.harvard.edu
SUMMARY:Mathematical Biology
DESCRIPTION:During Academic year 2018-19\, the CMSA will be hosting a Program on Mathematical Biology. \nJust over a century ago\, the biologist\, mathematician and philologist D’Arcy Thompson wrote “On growth and form”. The book was a visionary synthesis of the geometric biology of form at the time. It also served as a call for mathematical and physical approaches to understanding the evolution and development of shape. \nIn the century since its publication\, we have seen a revolution in biology following the discovery of the genetic code\, which has uncovered the molecular and cellular basis for life\, combined with the ability to probe the chemical\, structural\, and dynamical nature of molecules\, cells\, tissues and organs across scales. In parallel\, we have seen a blossoming of our understanding of spatiotemporal patterning in physical systems\, and a gradual unveiling of the complexity of physical form. And in mathematics and computation\, there has been a revolution in terms of posing and solving problems at the intersection of computational geometry\, statistics and inference.  So\, how far are we from realizing a descriptive\, predictive and controllable theory of biological shape? \nIn Fall 2018\, CMSA will focus on a program that aims at recent mathematical advances in describing shape using geometry and statistics in a biological context\, while also considering a range of physical theories that can predict biological shape at scales ranging from macromolecular assemblies to whole organ systems \nThe CMSA will be hosting three workshops as part of this program. The Workshop on Morphometrics\, Morphogenesis and Mathematics will take place on October 22-26.  \nA workshop on Morphogenesis: Geometry and Physics will take place on December 3-6\, 2018. \nA workshop on Invariance and Geometry in Sensation\, Action and Cognition will take place on April 15-17\, 2019.
URL:https://cmsa.fas.harvard.edu/event/mathematical-biology/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Programs
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20181022T083000
DTEND;TZID=America/New_York:20181024T140000
DTSTAMP:20260508T100604
CREATED:20230715T084844Z
LAST-MODIFIED:20250305T212456Z
UID:10000099-1540197000-1540389600@cmsa.fas.harvard.edu
SUMMARY:Workshop on Morphometrics\, Morphogenesis and Mathematics
DESCRIPTION:In Fall 2018\, the CMSA will host a Program on Mathematical Biology\, which aims to describe recent mathematical advances in using geometry and statistics in a biological context\, while also considering a range of physical theories that can predict biological shape at scales ranging from macromolecular assemblies to whole organ systems. \nThe plethora of natural shapes that surround us at every scale is both bewildering and astounding – from the electron micrograph of a polyhedral virus\, to the branching pattern of a gnarled tree to the convolutions in the brain. Even at the human scale\, the   shapes seen in a garden at the scale of a pollen grain\, a seed\, a sapling\, a root\, a flower or leaf are so numerous that “it is enough to drive the sanest man mad\,” wrote Darwin. Can we classify these shapes and understand their origins quantitatively? \nIn biology\, there is growing interest in and ability to quantify growth and form in the context of the size and shape of bacteria and other protists\, to understand how polymeric assemblies grow and shrink (in the cytoskeleton)\, and how cells divide\, change size and shape\, and move to organize tissues\, change their topology and geometry\, and link multiple scales and connect biochemical to mechanical aspects of these problems\, all in a self-regulated setting. \nTo understand these questions\, we need to describe shape (biomathematics)\, predict shape (biophysics)\, and design shape (bioengineering). \nFor example\, in mathematics there are some beautiful links to Nash’s embedding theorem\,  connections to quasi-conformal geometry\, Ricci flows and geometric PDE\, to Gromov’s h principle\, to geometrical singularities and singular geometries\, discrete and computational differential geometry\, to stochastic geometry and shape characterization (a la Grenander\, Mumford etc.). A nice question here is to use the large datasets (in 4D) and analyze them using ideas from statistical geometry (a la Taylor\, Adler) to look for similarities and differences across species during development\, and across evolution. \nIn physics\, there are questions of generalizing classical theories to include activity\, break the usual Galilean invariance\, as well as isotropy\, frame indifference\, homogeneity\, and create both agent (cell)-based and continuum theories for ordered\, active machines\, linking statistical to continuum mechanics\, and understanding the instabilities and patterns that arise. Active generalizations of liquid crystals\, polar materials\, polymers etc. are only just beginning to be explored and there are some nice physical analogs of biological growth/form that are yet to be studied. \nThe CMSA will be hosting a Workshop on Morphometrics\, Morphogenesis and Mathematics from October 22-24\, 2018 at the Center of Mathematical Sciences and Applications\, located at 20 Garden Street\, Cambridge\, MA. \nThe workshop is organized by L. Mahadevan (Harvard)\, O. Pourquie (Harvard)\, A. Srivastava (Florida). \nVideos of the talks\nConfirmed Speakers:\n\nArkhat Abzhanov\, Imperial College\nSiobhan Braybrook\, UCLA\nCassandra Extavour\, Harvard\nAnjali Goswami\, University College London\nDavid Gu\, Stony Brook\nJukka Jernvall\, Helsinki\nEric Klassen\, Florida State\nSayan Mukherjee\, Duke\nPeter Olver\, U Minnesota\nNipam Patel\, Berkeley\nStephanie Pierce\, Harvard\nKaren Sears\, UCLA\nAlain Trouve\, ENS-Cachan\, France\nLaurent Younes\, Johns Hopkins
URL:https://cmsa.fas.harvard.edu/event/workshop-on-morphometrics-morphogenesis-and-mathematics/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Programs,Workshop
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180929T083000
DTEND;TZID=America/New_York:20180930T150000
DTSTAMP:20260508T100604
CREATED:20230715T084506Z
LAST-MODIFIED:20250328T145116Z
UID:10000090-1538209800-1538319600@cmsa.fas.harvard.edu
SUMMARY:F-Theory Workshop
DESCRIPTION:The CMSA hosted an F-Theory workshop September 29-30\, 2018. The workshop was held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. \nYoutube Playlist  \nOrganizers: \n\nPaolo Aluffi (Florida State)\nLara B. Anderson (Virginia Tech)\nMboyo Esole (Northeastern)\nShing-Tung Yau (Harvard)\n\nSpeakers: \n\nMirjam Cvetic\, University of Pennsylvania\nTommaso de Fernex\, University of Utah\nJames Gray\, Virginia Tech\nJonathan Heckman\, University of Pennsylvania\nMonica Kang\, Harvard University\nSándor Kovács\, University of Washington\nAnatoly Libgober\, UIC\nMatilde Marcolli\, Caltech\, University of Toronto\, and Perimeter Institute\nWashington Taylor\, MIT\nCumrun Vafa\, Harvard University
URL:https://cmsa.fas.harvard.edu/event/f-theory-conference/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180827T092000
DTEND;TZID=America/New_York:20180828T151500
DTSTAMP:20260508T100604
CREATED:20230715T084116Z
LAST-MODIFIED:20250305T184118Z
UID:10000089-1535361600-1535469300@cmsa.fas.harvard.edu
SUMMARY:Kickoff Workshop on Topology and Quantum Phases of Matter
DESCRIPTION:On August 27-28\, 2018\, the CMSA will be hosting a Kickoff workshop on Topology and Quantum Phases of Matter. New ideas rooted in topology have recently had a big impact on condensed matter physics\, and have highlighted new connections with high energy physics\, mathematics and quantum information theory. Additionally\, these ideas have found applications in the design of photonic systems and of materials with novel mechanical properties. The aim of this program will be to deepen these connections by fostering discussion and seeding new collaborations within and across disciplines. \nThis workshop is a part of the CMSA’s program on Program on Topological Aspects of Condensed Matter\,  and will be the first of two workshops\, in addition to a visitor program and seminars. \nThe workshop will be held in room G10 of the CMSA\, located at 20 Garden Street\, Cambridge\, MA. \nSpeakers:  \n\nZhen Bi\, MIT\nMeng Cheng\, Yale\nDima Feldman\, Brown\nDominic Else\, UCSB\nLiang Fu\, MIT\nFabian Grusdt\, Harvard\nYing Fei Gu\, Harvard\nBert Halperin\, Harvard\nAnton Kapustin\, Caltech\nPatrick Lee\, MIT\nL. Mahadevan\, Harvard\nBrad Marston\, Brown\nMax Metlitski\, MIT\nEmil V. Prodan\, Yeshiva\nAchim Rosch\, University of Cologne\nMathias Scheurer\, Harvard\nMarin Soljacic\, MIT\nX. G. Wen\, MIT\nCenke Xu\, UCSB\nFrank Zhang\, Cornell
URL:https://cmsa.fas.harvard.edu/event/kickoff-workshop-on-topology-and-quantum-phases-of-matter/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Topological-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180413T163000
DTEND;TZID=America/New_York:20180413T173000
DTSTAMP:20260508T100604
CREATED:20240213T065558Z
LAST-MODIFIED:20240514T185400Z
UID:10002143-1523637000-1523640600@cmsa.fas.harvard.edu
SUMMARY:On the fibration structure of known Calabi-Yau threefolds
DESCRIPTION:Speaker: Washington Tayor (MIT) \nTitle: On the fibration structure of known Calabi-Yau threefolds \nAbstract: In recent years\, there is increasing evidence from a variety of directions\, including the physics of F-theory and new generalized CICY constructions\, that a large fraction of known Calabi-Yau manifolds have a genus one or elliptic fibration. In this talk I will describe recent work with Yu-Chien Huang on a systematic analysis of the fibration structure of known toric hypersurface Calabi-Yau threefolds. Among other results\, this analysis shows that every known Calabi-Yau threefold with either Hodge number exceeding 150 is genus one or elliptically fibered\, and suggests that the fraction of Calabi-Yau threefolds that are not genus one or elliptically fibered decreases roughly exponentially with h_{11}. I will also make some comments on the connection with the structure of triple intersection numbers in Calabi-Yau threefolds.
URL:https://cmsa.fas.harvard.edu/event/4-18-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/2018_04_13_11_01_32-e1523633302205.png
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180411T163000
DTEND;TZID=America/New_York:20180411T173000
DTSTAMP:20260508T100604
CREATED:20240213T065052Z
LAST-MODIFIED:20240515T144439Z
UID:10002134-1523464200-1523467800@cmsa.fas.harvard.edu
SUMMARY:Graph Structure in Polynomial Systems: Chordal Networks
DESCRIPTION:Speaker: Pablo Parillo (MIT) \nTitle: Graph Structure in Polynomial Systems: Chordal Networks \nAbstract: The sparsity structure of a system of polynomial equations or an optimization problem can be naturally described by a graph summarizing the interactions among the decision variables. It is natural to wonder whether the structure of this graph might help in computational algebraic geometry tasks (e.g.\, in solving the system). In this lecture we will provide a gentle introduction to this area\, focused on the key notions of chordality and treewidth\, which are of great importance in related areas such as numerical linear algebra\, database theory\, constraint satisfaction\, and graphical models. In particular\, we will discuss “chordal networks”\, a novel representation of structured polynomial systems that provides a computationally convenient decomposition of a polynomial ideal into simpler (triangular) polynomial sets\, while maintaining its underlying graphical structure. As we will illustrate through examples from different application domains\, algorithms based on chordal networks can significantly outperform existing techniques. Based on joint work with Diego Cifuentes (MIT).
URL:https://cmsa.fas.harvard.edu/event/4-11-2018-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/2018_04_10_09_58_15-e1523369654177.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180409T090000
DTEND;TZID=America/New_York:20180413T153000
DTSTAMP:20260508T100604
CREATED:20230717T175359Z
LAST-MODIFIED:20250305T214334Z
UID:10000079-1523264400-1523633400@cmsa.fas.harvard.edu
SUMMARY:Workshop on Coding and Information Theory
DESCRIPTION:The workshop on coding and information theory will take place April 9-13\, 2018 at the Center of Mathematical Sciences and Applications\, located at 20 Garden Street\, Cambridge\, MA. \nThis workshop will focus on new developments in coding and information theory that sit at the intersection of combinatorics and complexity\, and will bring together researchers from several communities — coding theory\, information theory\, combinatorics\, and complexity theory — to exchange ideas and form collaborations to attack these problems. \nSquarely in this intersection of combinatorics and complexity\, locally testable/correctable codes and list-decodable codes both have deep connections to (and in some cases\, direct motivation from) complexity theory and pseudorandomness\, and recent progress in these areas has directly exploited and explored connections to combinatorics and graph theory.  One goal of this workshop is to push ahead on these and other topics that are in the purview of the year-long program.  Another goal is to highlight (a subset of) topics in coding and information theory which are especially ripe for collaboration between these communities.  Examples of such topics include polar codes; new results on Reed-Muller codes and their thresholds; coding for distributed storage and for DNA memories; coding for deletions and synchronization errors; storage capacity of graphs; zero-error information theory; bounds on codes using semidefinite programming; tensorization in distributed source and channel coding; and applications of information-theoretic methods in probability and combinatorics.  All these topics have attracted a great deal of recent interest in the coding and information theory communities\, and have rich connections to combinatorics and complexity which could benefit from further exploration and collaboration. \nParticipation: The workshop is open to participation by all interested researchers\, subject to capacity. \nA list of lodging options convenient to the Center can also be found on our recommended lodgings page. \nConfirmed participants include: \n\nEmmanuel Abbe\, Princeton University\nSimeon Ball\, Universitat Politècnica de Catalunya\nBoris Bukh\, Carnegie Mellon University\nMahdi Cheraghchi\, Imperial College London\nSivakanth Gopi\, Princeton University\nElena Grigorescu\, University of Purdue\nHamed Hassani\, University of Pennsylvania\nNavin Kashyap\, Indian Institute of Science\nYoung-Han Kim\, University of California\, San Diego\nSwastik Kopparty\, Rutgers University\nNati Linial\, Hebrew University of Jerusalem\nShachar Lovett\, University of California\, San Diego\nWilliam Martin\, Worcester Polytechnic Institute\nArya Mazumdar\, University of Massachusetts at Amherst\nOr Meir\, University of Haifa\nOlgica Milenkovic\, ECE Illinois\nChandra Nair\, Chinese University of Hong Kong\nYuval Peres\, Microsoft Research\nYury Polyanskiy\, Massachusetts Institute of Technology\nMaxim Raginsky\, University of Illinois at Urbana-Champaign\nSankeerth Rao Karingula\, UC San Diego\nAnkit Singh Rawat\, MIT\nNoga Ron-Zewi\, University of Haifa\nRon Roth\, Israel Institute of Technology\nAtri Rudra\, State University of New York\, Buffalo\nAlex Samorodnitsky\, Hebrew University of Jerusalem\nItzhak Tamo\, Tel Aviv University\nAmnon Ta-Shma\, Tel Aviv University\nHimanshu Tyagi\, Indian Institute of Science\nDavid Zuckerman\, University of Texas at Austin
URL:https://cmsa.fas.harvard.edu/event/workshop-on-coding-and-information-theory/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Workshop
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END:VCALENDAR