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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240419T120000
DTEND;TZID=America/New_York:20240419T130000
DTSTAMP:20260504T175911
CREATED:20240305T155850Z
LAST-MODIFIED:20240418T194607Z
UID:10000689-1713528000-1713531600@cmsa.fas.harvard.edu
SUMMARY:Member Seminar
DESCRIPTION:CMSA Member Seminar \nSpeaker: Sunghyuk Park\, Harvard CMSA \nTitle: 3D quantum trace map \nAbstract: I will speak about my recent work (joint with Sam Panitch) constructing the 3d quantum trace map\, a homomorphism from the Kauffman bracket skein module of an ideally triangulated 3-manifold to its (square root) quantum gluing module\, thereby giving a precise relationship between the two quantizations of the character variety of ideally triangulated 3-manifolds. Our construction is based on the study of stated skein modules and their behavior under splitting\, especially into face suspensions. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-04.19.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240418T101500
DTEND;TZID=America/New_York:20240418T113000
DTSTAMP:20260504T175911
CREATED:20240415T133328Z
LAST-MODIFIED:20240813T153315Z
UID:10000887-1713435300-1713439800@cmsa.fas.harvard.edu
SUMMARY:Geometric local systems on very general curves
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Aaron Landesman\, MIT \nTitle: Geometric local systems on very general curves \nAbstract: What is the smallest genus h of a non-isotrivial curve over the generic genus g curve? In joint work with Daniel Litt\, we show h is more than $\sqrt{g}$ by proving amore general result about variations of Hodge structure on sufficiently general curves. As a consequence\, we show that local systems on a sufficiently general curve of geometric origin are not Zariski dense in the character variety parameterizing such local systems. This gives counterexamples to conjectures of Esnault-Kerz and Budur-Wang.
URL:https://cmsa.fas.harvard.edu/event/agst-41824/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Algebraic-Geometry-in-String-Theory-04.18.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240412T120000
DTEND;TZID=America/New_York:20240412T130000
DTSTAMP:20260504T175911
CREATED:20240305T155803Z
LAST-MODIFIED:20240410T234826Z
UID:10000687-1712923200-1712926800@cmsa.fas.harvard.edu
SUMMARY:Global weak solutions of 3+1 dimensional vacuum Einstein equations 
DESCRIPTION:CMSA Member Seminar \nSpeaker: Puskar Mondal \nTitle: Global weak solutions of 3+1 dimensional vacuum Einstein equations \nAbstract: It is important to understand if the `solutions’ of non-linear evolutionary PDEs persist for all time or become extinct in finite time through the blow-up of invariant entities. Now the question of this global existence or finite time blow up in the PDE settings is well defined if the regularity of the solution is specified. Most physically interesting scenarios demand control of the point-wise behavior of the solution. Unfortunately\, most times this level of regularity is notoriously difficult to obtain for non-linear equations. In this talk\, I will discuss very low regularity solutions namely distributional (or weak) solutions of vacuum Einsten’s equations in 3+1 dimensions. I prove that on a globally hyperbolic spacetime foliated by closed connected oriented negative Yamabe slices\, weak solutions of the Einstein equations exist for all time. The monotonicity of a Coercive Entity called reduced Hamiltonian that controls the minimum regularity required for the weak solution is employed. This is in the same spirit as Leray’s global weak solutions of Navier-Stokes in 3+1 dimensions and the first result in the context of Einstein equations.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-04.12.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240411T103000
DTEND;TZID=America/New_York:20240411T113000
DTSTAMP:20260504T175911
CREATED:20240410T234504Z
LAST-MODIFIED:20240410T234742Z
UID:10000886-1712831400-1712835000@cmsa.fas.harvard.edu
SUMMARY:Mirror symmetry for fibrations and degenerations of K3 surfaces
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Alan Thompson (Loughborough University) \nTitle: Mirror symmetry for fibrations and degenerations of K3 surfaces \nAbstract: In 2016\, Doran\, Harder\, and I conjectured a mirror symmetric relationship between Tyurin degenerations and splittings of codimension 1 fibrations on Calabi-Yau manifolds. In this talk I will discuss recent work to make this conjecture rigorous in the case of K3 surfaces. I will give a precise definition of what it means for a Tyurin degeneration of K3’s to be mirror to a splitting of an elliptically fibred K3\, and show that this definition enjoys the following compatibilities with existing mirror symmetric theories: 1) The general fibre of the Tyurin degeneration is mirror to the elliptically fibred K3\, in the sense of Dolgachev-Nikulin. 2) Components of the Tyurin degeneration and pieces of the splitting satisfy a homological version of the (quasi-) Fano-LG correspondence. 3) Components of the Tyurin degeneration which are weak del Pezzo are mirror to pieces of the splitting that arise as restrictions of the corresponding lattice polarised LG models to discs. This is joint work with Luca Giovenzana.
URL:https://cmsa.fas.harvard.edu/event/agst-41124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-04.11.2024_Page_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240405T120000
DTEND;TZID=America/New_York:20240405T130000
DTSTAMP:20260504T175911
CREATED:20240213T165524Z
LAST-MODIFIED:20240403T143010Z
UID:10000685-1712318400-1712322000@cmsa.fas.harvard.edu
SUMMARY:Phase diagram and confining strings in a minimal model of nematopolar matter
DESCRIPTION:CMSA Member Seminar \nSpeaker: Farzan Vafa \nTitle: Phase diagram and confining strings in a minimal model of nematopolar matter \nAbstract: We investigate a minimal model of a nematopolar system. We analytically uncover a phase diagram consisting of a locked phase where the polar order and nematic order are locked\, and unlocked phases which could be ordered or disordered. In particular\, we develop two complementary perspectives on the locked phase: (i) the nematic order induces polar order\, (ii) in the locked phase\, all 1/2 integral nematic topological charges are confined. In particular\, a polar +1 defect fattens from a point along a string with constant tension and confines a pair of nematic +1/2 defects at its ends.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-4524/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-04.05.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240404T103000
DTEND;TZID=America/New_York:20240404T113000
DTSTAMP:20260504T175911
CREATED:20240325T190117Z
LAST-MODIFIED:20240326T153652Z
UID:10000885-1712226600-1712230200@cmsa.fas.harvard.edu
SUMMARY:Derived categories of genus one curves and torsors over abelian varieties
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Jonathan Rosenberg\, University of Maryland \n\nTitle: Derived categories of genus one curves and torsors over abelian varieties\n \nAbstract:  Studying orientifold string theories on elliptic curves or abelian\nvarieties motivates studying the derived category of coherent sheaves on\na genus one curve or a torsor over an abelian variety over the reals\n(as opposed to the complex numbers).\n\nIn joint work with Nirnajan Ramachandran (to appear in MRL)\, we show that\na genus one curve over a perfect field determines a class in the relative\nBrauer group of the Jacobian elliptic curve\, and that there is a natural\nMukai-type derived equivalence between the original genus one curve\nand the Jacobian twisted by the Brauer class.  The proof extends to\ntorsors over abelian varieties (of any dimension).
URL:https://cmsa.fas.harvard.edu/event/agst-4224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Algebraic-Geometry-in-String-Theory-04.04.24-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240322T120000
DTEND;TZID=America/New_York:20240322T130000
DTSTAMP:20260504T175911
CREATED:20240213T165334Z
LAST-MODIFIED:20240321T200536Z
UID:10000681-1711108800-1711112400@cmsa.fas.harvard.edu
SUMMARY:Modularity and Fibrations in Mirror Symmetry
DESCRIPTION:CMSA Member Seminar \nSpeaker: Chuck Doran (Harvard CMSA) \nTitle: Modularity and Fibrations in Mirror Symmetry \nAbstract: We will introduce appearances of modularity in the study both of families of Calabi-Yau threefolds and of their enumerative invariants.  An important role is played by the structure of fibrations and the DHT fibration-degeneration mirror correspondence\, which clarifies how these notions of modularity are (and are not) related.  This is joint work with Boris Pioline and Thorsten Schimannek.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-32224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-03.22.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240321T103000
DTEND;TZID=America/New_York:20240321T113000
DTSTAMP:20260504T175911
CREATED:20240318T205345Z
LAST-MODIFIED:20240403T173032Z
UID:10000883-1711017000-1711020600@cmsa.fas.harvard.edu
SUMMARY:The KSBA moduli space of log Calabi-Yau surfaces
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Pierrick Bousseau\, University of Georgia \nTitle: The KSBA moduli space of log Calabi-Yau surfaces \nAbstract: The KSBA moduli space\, introduced by Kollár–Shepherd-Barron\, and Alexeev\, is a natural generalization of “the moduli space of stable curves” to higher dimensions. It parametrizes stable pairs (X\,B)\, where X is a projective algebraic variety satisfying certain conditions and B is a divisor such that K_X+B is ample. This moduli space is described concretely only in a handful of situations: for instance\, if X is a toric variety and B=D+\epsilon C\, where D is the toric boundary divisor and C is an ample divisor\, it is shown by Alexeev that the KSBA moduli space is a toric variety. Generally\, for a log Calabi-Yau variety (X\,D) consisting of a projective variety X and an anticanonical divisor D\, with B=D+\epsilon C where C is an ample divisor\, it was conjectured by Hacking–Keel–Yu that the KSBA moduli space is still toric (up to passing to a finite cover). In joint work with Alexeev and Argüz\, we prove this conjecture for all log Calabi-Yau surfaces. This uses tools from the minimal model program\, log smooth deformation theory and mirror symmetry. \n 
URL:https://cmsa.fas.harvard.edu/event/agst-32124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-03.21.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240308T120000
DTEND;TZID=America/New_York:20240308T130000
DTSTAMP:20260504T175911
CREATED:20240213T165030Z
LAST-MODIFIED:20240307T170714Z
UID:10000677-1709899200-1709902800@cmsa.fas.harvard.edu
SUMMARY:Symmetry in quantum field theory
DESCRIPTION:CMSA Member Seminar \nSpeaker: Dan Freed (Harvard Mathematics and CMSA) \nTitle: Symmetry in quantum field theory \nAbstract: In joint work with Greg Moore and Constantin Teleman we show how ideas and techniques in topological field theory apply to the study of symmetry in quantum field theory. I will discuss how this came about\, beginning with some discussion of symmetry in mathematics more generally\, and give some examples.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-3824/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-03.08.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240307T103000
DTEND;TZID=America/New_York:20240307T113000
DTSTAMP:20260504T175911
CREATED:20240214T150457Z
LAST-MODIFIED:20240228T195719Z
UID:10000881-1709807400-1709811000@cmsa.fas.harvard.edu
SUMMARY:Geometric construction of toric NCRs
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Jesse Huang\, University of Alberta \nTitle: Geometric construction of toric NCRs \nAbstract: The Rouquier dimension of a toric variety is recently shown to be achieved by the Frobenius pushforward of O via coherent-constructible correspondence. From the perspective of noncommutative geometry\, this result leads to a geometric construction of toric NCR of the invariant ring of the Cox ring with respect to a multi-grading which also gives the information about its global dimension. From the perspective of mirror symmetry\, the same construction provides a universal “wall skeleton” capturing VGIT wall-crossings\, which contains a window for each chamber as a full subcategory. From the perspective of commutative algebra\, the same construction indicates the existence of virtual resolutions of the multigraded diagonal bimodule\, which agrees with a recent result of Hanlon-Hicks-Larzarev constructing one such resolution explicitly. In this talk\, I will survey these perspectives. The talk is based on joint works with P. Zhou\, joint works with D. Favero\, and work in progress with D. Favero. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/agst-3724/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-03.07.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240301T120000
DTEND;TZID=America/New_York:20240301T130000
DTSTAMP:20260504T175911
CREATED:20240123T192912Z
LAST-MODIFIED:20240227T161522Z
UID:10000675-1709294400-1709298000@cmsa.fas.harvard.edu
SUMMARY:Contract Design in Combinatorial Settings
DESCRIPTION:CMSA Member Seminar \nSpeaker: Tomer Ezra (Harvard CMSA) \nTitle: Contract Design in Combinatorial Settings \nAbstract: We study two combinatorial settings of the contract design problem\, in which a principal wants to delegate the execution of a costly task. In the first setting\, the principal delegates the task to an agent that can take any subset of a given set of unobservable actions\, each of which has an associated cost. The principal receives a reward which is a combinatorial function of the actions taken by the agent. In the second setting\, we study the single-principal multi-agent contract problem\, in which the principal motivates a team of agents to exert effort toward a given task. We design (approximately) optimal algorithms for both settings along with impossibility results for various classes of combinatorial functions. \nThis talk is based on joint works with Paul Duetting\, Michal Feldman\, Thomas Kesselheim and Maya Schlesinger.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-3124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-03.01.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240229T103000
DTEND;TZID=America/New_York:20240229T113000
DTSTAMP:20260504T175911
CREATED:20240226T153440Z
LAST-MODIFIED:20240226T153514Z
UID:10000880-1709202600-1709206200@cmsa.fas.harvard.edu
SUMMARY:Classifying curves on Fano varieties
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Brian Lehmann (Boston College) \nTitle: Classifying curves on Fano varieties \nAbstract: How can we understand the set of curves on a Fano variety? One perspective is provided by Geometric Manin’s Conjecture\, a collection of conjectures with roots in arithmetic and topology.  While I will mention some recent progress\, the main focus will be developing a conceptual framework for thinking about our question.
URL:https://cmsa.fas.harvard.edu/event/agst-22924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-02.29.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240223T120000
DTEND;TZID=America/New_York:20240223T130000
DTSTAMP:20260504T175911
CREATED:20240123T192604Z
LAST-MODIFIED:20240220T160057Z
UID:10000673-1708689600-1708693200@cmsa.fas.harvard.edu
SUMMARY:Integrability and Hidden Symmetries in Black Hole Dynamics
DESCRIPTION:CMSA Member Seminar \nSpeaker: Uri Kol (Harvard CMSA) \nTitle: Integrability and Hidden Symmetries in Black Hole Dynamics \nAbstract: The last decade has produced a number of remarkable discoveries\, such as the first direct observation of gravitational waves by the LIGO/Virgo collaboration and the first black hole image taken by the Event Horizon Telescope. These discoveries mark the beginning of a new precision era in black hole physics\, which is expected to develop further by future experiments such as LISA\, the Einstein Telescope and Cosmic Explorer. \n  \nIn the era of precision black hole measurements\, there is a need for precision theoretical methods and accurate predictions. In this talk I will describe an integrable sector of the gravitational scattering problem – analogous to the hydrogen atom in quantum mechanics – in which exact predictions can be made\, and the implications for astrophysical black holes and binary mergers.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-22324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-02.23.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240222T103000
DTEND;TZID=America/New_York:20240222T113000
DTSTAMP:20260504T175911
CREATED:20240215T152956Z
LAST-MODIFIED:20240216T164834Z
UID:10000879-1708597800-1708601400@cmsa.fas.harvard.edu
SUMMARY:Geometric origins of values of the Riemann Zeta functions at positive integers
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Yan Zhou\, Northeastern \nTitle: Geometric origins of values of the Riemann Zeta functions at positive integers \nAbstract: Given a Fano manifold\, Iritani proposed that the asymptotic behavior of solutions to the quantum differential equation of the Fano should be given by the so-called ‘Gamma class’ in its cohomology ring. Later\, Abouzaid-Ganatra-Iritani-Sheridan reformulated the ‘Gamma conjecture’ for Calabi-Yau manifolds via the tropical SYZ mirror symmetry and proposed that values of the Riemann Zeta function at positive integers have geometric origins in the tropical periods and singularities of the SYZ geometry. In this talk\, we will first review the content of the Gamma conjecture. Then\, we will discuss the first step of generalizing AGIS’ approach to Gamma conjecture for the Gross-Siebert mirror families of a Fano manifold in dimension 2 cases\, based on joint work with Bohan Fang and Junxiao Wang.
URL:https://cmsa.fas.harvard.edu/event/agst-22224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-02.22.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240216T120000
DTEND;TZID=America/New_York:20240216T130000
DTSTAMP:20260504T175911
CREATED:20240213T164834Z
LAST-MODIFIED:20240215T182409Z
UID:10000671-1708084800-1708088400@cmsa.fas.harvard.edu
SUMMARY:Symmetries and algebraicity in the flux landscape
DESCRIPTION:CMSA Member Seminar \nSpeaker: Damian van de Heisteeg (Harvard CMSA) \nTitle: Symmetries and algebraicity in the flux landscape \nAbstract: In this talk I consider potentials coming from fluxes in string theory. The minima of these potentials trace out special loci in the moduli space of Calabi-Yau manifolds. I discuss the structure that underlies these minima from a Hodge-theoretic point of view. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-21624/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-02.15.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240209T120000
DTEND;TZID=America/New_York:20240209T130000
DTSTAMP:20260504T175911
CREATED:20240208T143028Z
LAST-MODIFIED:20240208T143041Z
UID:10000669-1707480000-1707483600@cmsa.fas.harvard.edu
SUMMARY:The spectrum of some nonlinear random matrices
DESCRIPTION:CMSA Member Seminar \nSpeaker: Benjamin McKenna (Harvard) \nTitle: The spectrum of some nonlinear random matrices \nAbstract: Modern data science often requires one to consider “nonlinear random matrices\,” a broad term for random-matrix models whose construction involves a nonlinear function applied entrywise. Such models are typically far from classical random matrix theory\, and in principle entrywise nonlinearities can affect the eigenvalues in a complicated way. However\, recent years have seen a number of results on nonlinear models whose spectrum is surprisingly simple. We give one such result\, emphasizing general random-matrix techniques like free probability and orthogonal polynomials. Joint work with Sofiia Dubova\, Yue M. Lu\, and Horng-Tzer Yau.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-2924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240208T103000
DTEND;TZID=America/New_York:20240208T113000
DTSTAMP:20260504T175911
CREATED:20240129T162946Z
LAST-MODIFIED:20240205T190443Z
UID:10000877-1707388200-1707391800@cmsa.fas.harvard.edu
SUMMARY:On (semi)stable reduction and KSBA moduli in positive characteristic
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Iacopo Brivio (Harvard CMSA) \nTitle: On (semi)stable reduction and KSBA moduli in positive characteristic \nAbstract: The moduli space M_g of genus g stable curves is perhaps the most studied of all algebraic varieties. Its higher-dimensional generalization is the moduli functor M_{n\,v} of n-dimension stable varieties of volume v. It was proven only recently\, and thanks to the joint effort of many over many years\, that such functors are represented by projective algebraic spaces when working over the complex numbers. In this talk I will give some examples showing that the same moduli functors in positive characteristic are not even proper and\, more in general\, that the MMP fails to be functorial even in very nice families. In the second part I am going to explore some possible generalizations of the notion of stable variety that could be used as a replacement in positive characteristic.
URL:https://cmsa.fas.harvard.edu/event/agst-2824/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240202T120000
DTEND;TZID=America/New_York:20240202T130000
DTSTAMP:20260504T175911
CREATED:20240123T192516Z
LAST-MODIFIED:20240201T171531Z
UID:10000667-1706875200-1706878800@cmsa.fas.harvard.edu
SUMMARY:On complete Calabi-Yau metrics and Monge-Ampere equations
DESCRIPTION:CMSA Member Seminar \nSpeaker: Freid Tong (Harvard CMSA) \nTitle: On complete Calabi-Yau metrics and Monge-Ampere equations \nAbstract: Calabi-Yau metrics are central objects in K\”ahler geometry and also string theory. The existence of Calabi-Yau metrics on compact manifolds was answered by Yau in his solution of the Calabi conjecture\, but the situation in the non-compact setting is much more delicate\, and many questions related to the existence and uniqueness of non-compact Calabi-Yau metrics remain unanswered. I will give an introduction to this subject and discuss some ongoing joint work with T. Collins and S.-T. Yau\, on a new relationship between complete Calabi-Yau metrics and a new Monge-Ampere equation.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-2224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar_2224.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240201T103000
DTEND;TZID=America/New_York:20240201T113000
DTSTAMP:20260504T175911
CREATED:20240119T213407Z
LAST-MODIFIED:20240122T183212Z
UID:10000876-1706783400-1706787000@cmsa.fas.harvard.edu
SUMMARY:Algebraic billiards and dynamical degrees
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Max Weinreich (Harvard) \nTitle: Algebraic billiards and dynamical degrees \nAbstract: Billiards is one of the most-studied dynamical systems\, modeling the behavior of a point particle bouncing around some space. If the space is a plane region bounded by an algebraic curve\, then we may use techniques from algebraic geometry to study its billiards map. We explain how to view billiards as a complex algebraic correspondence\, and we prove upper and lower bounds on the dynamical degree\, the growth rate of the degrees of the iterates\, in terms of the degree of the boundary curve. These degree growth rates are studied in mathematical physics\, broadly speaking\, as a way to identify integrable (exactly solvable) physical models. In our setting\, this theory gives us an upper bound on the entropy\, or chaos\, of billiards in curves.
URL:https://cmsa.fas.harvard.edu/event/agst-2124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/Algebraic-Geometry-in-String-Theory-02.01.2024_Page_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240126T120000
DTEND;TZID=America/New_York:20240126T130000
DTSTAMP:20260504T175911
CREATED:20240102T203315Z
LAST-MODIFIED:20240125T174129Z
UID:10000803-1706270400-1706274000@cmsa.fas.harvard.edu
SUMMARY:Anti-Iitaka conjecture in positive characteristic
DESCRIPTION:CMSA Member Seminar \nSpeaker: Iacopo Brivio (Harvard) \nTitle: Anti-Iitaka conjecture in positive characteristic \nAbstract: Given a smooth projective variety\, its Kodaira dimension kappa(K_X) is an important invariant that measures the rate of growth of m-pluricanonical forms as a function of m. It serves as an higher-dimensional generalization of the genus of a Riemann surface. If f : X –> Y is a fibration with general fiber F\, a famous conjecture of Iitaka predicts the inequality kappa(K_X) \geq kappa(K_Y) + kappa(K_F). More recently it was shown by Chang that\, if the stable base locus of -K_X is vertical\, then the inequality kappa(-K_X) \leq kappa(-K_Y) + kappa(-K_F) holds. Both Iitaka’s conjecture and Chang’s theorem are known to fail in positive characteristic. In this talk I will explain how one can recover Chang’s theorem for a class of “tame” fibrations in characteristic p > 0. This is based on joint work with M. Benozzo and C.-K. Chang.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-12624/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-01.26.24.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231211T103000
DTEND;TZID=America/New_York:20231211T113000
DTSTAMP:20260504T175911
CREATED:20240221T112820Z
LAST-MODIFIED:20240221T112900Z
UID:10002782-1702290600-1702294200@cmsa.fas.harvard.edu
SUMMARY:M-theory on nodal Calabi-Yau 3-folds and torsion refined GV-invariants
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Thorsten Schimannek (Utrecht University) \n\nTitle: M-theory on nodal Calabi-Yau 3-folds and torsion refined GV-invariants \nAbstract: The physics of M-theory and Type IIA strings on a projective nodal CY 3-folds is determined by the geometry of a small resolution\, even if the latter is not Kähler. We will demonstrate this explicitly in the context of a family of Calabi-Yau double covers of P^3. Using conifold transitions\, we prove that the exceptional curves in any small resolution are torsion while M-theory develops a discrete gauge symmetry.This leads to a torsion refinement of the ordinary Gopakumar-Vafa invariants\, that is associated to the singular Calabi-Yau and captures the enumerative geometry of the non-Kähler resolutions. We further argue that twisted circle compactifications of the 5d theory are dual to IIA compactifications on the nodal CY 3-fold with a flat but topologically non-trivial B-field. As a result\, the torsion refined invariants are encoded in the topological string partition functions with different choices for the global topology of a flat B-field. \nThe talk is based on 2108.09311\, 2212.08655 (with S. Katz\, A. Klemm\, and E. Sharpe) and 2307.00047 (with S. Katz).
URL:https://cmsa.fas.harvard.edu/event/agst-121123/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-12.11.2023-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231204T103000
DTEND;TZID=America/New_York:20231204T113000
DTSTAMP:20260504T175911
CREATED:20240222T065433Z
LAST-MODIFIED:20240222T152910Z
UID:10002786-1701685800-1701689400@cmsa.fas.harvard.edu
SUMMARY:CM-minimizers and standard models of Fano fibrations over curves
DESCRIPTION:Algebraic Geometry in String Theory Seminar \n\nSpeaker: Maksym Fedorchuk (Boston College) \nTitle: CM-minimizers and standard models of Fano fibrations over curves \nAbstract: A recent achievement in K-stability of Fano varieties is an algebro-geometric construction of a projective moduli space of K-polystable Fanos. The ample line bundle on this moduli space is the CM line bundle of Tian. One of the consequences of the general theory is that given a family of K-stable Fanos over a punctured curve\, the polystable filling is the one that minimizes the degree of the CM line bundle after every finite base change. A natural question is to ask what are the CM-minimizers without base change. In answering this question\, we arrive at a theory of Koll\’ar stability for fibrations over one-dimensional bases\, and standard models of Fano fibrations. I will explain the joint work with Hamid Abban and Igor Krylov in which we show that the CM-minimizers for del Pezzo fibrations are Corti’s standard models and related work in progress on quartic threefold hypersurfaces. \n\n 
URL:https://cmsa.fas.harvard.edu/event/agst-12423/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/CMSA-AGIST-12.04.23-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231127T103000
DTEND;TZID=America/New_York:20231127T113000
DTSTAMP:20260504T175911
CREATED:20240221T113319Z
LAST-MODIFIED:20240221T113411Z
UID:10002783-1701081000-1701084600@cmsa.fas.harvard.edu
SUMMARY:A p-adic Laplacian on the Tate curve
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: An Huang (Brandeis) \nPre-talk Speaker: TBA: 10:00-10:30 am \n\n\nTitle: A p-adic Laplacian on the Tate curve \nAbstract: We shall first explain the relation between a family of deformations of genus zero p-adic string worldsheet action and Tate’s thesis. We then propose a genus one p-adic string worldsheet action. The key is the definition of a p-adic Laplacian operator on the Tate curve. We show that the genus one p-adic Green’s function exists\, is unique under some obvious constraints\, is locally constant off diagonal\, and has a reflection symmetry. It can also be numerically computed exactly off the diagonal\, thanks to some simplifications due to the p-adic setup. Numerics suggest that at least in some special cases\, the asymptotic behavior of the Green’s function near the diagonal is a direct p-adic counterpart of the familiar Archimedean case\, although the p-adic Laplacian is not a local operator. Joint work in progress with Rebecca Rohrlich.
URL:https://cmsa.fas.harvard.edu/event/agst-112723/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-11.27.2023.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231113T103000
DTEND;TZID=America/New_York:20231113T113000
DTSTAMP:20260504T175911
CREATED:20240222T070558Z
LAST-MODIFIED:20240222T070558Z
UID:10002787-1699871400-1699875000@cmsa.fas.harvard.edu
SUMMARY:Stacky small resolutions of determinantal octic double solids and noncommutative Gopakumar-Vafa invariants
DESCRIPTION:Algebraic Geometry in String Theory Seminar \n\nSpeaker: Sheldon Katz\, UIUC \nTitle: Stacky small resolutions of determinantal octic double solids and noncommutative Gopakumar-Vafa invariants \nAbstract:  A determinantal octic double solid is the double cover X of P^3 branched along the degree 8 determinant of a symmetric matrix of homogeneous forms on P^3.  These X are nodal CY threefolds which do not admit a projective small resolution.  B-model techniques can be applied to compute GV invariants up to g \le 32.  This raises the question: what is the geometric meaning of these invariants? \nEvidence suggests that these enumerative invariants are associated with moduli stacks of coherent sheaves of modules over a sheaf B of noncommutative algebras on X constructed by Kuznetsov.  One of these moduli stacks is a stacky small resolution X’ of X itself.  This leads to another geometric interpretation of the invariants as being associated with moduli of sheaves on X’ twisted by a Brauer class.  Geometric computations based on these working definitions always agree with the B-model computations. \nThis talk is based on joint work with Albrecht Klemm\, Thorsten Schimannek\, and Eric Sharpe. \n\n 
URL:https://cmsa.fas.harvard.edu/event/agst-111323/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-11.13.2023.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231106T103000
DTEND;TZID=America/New_York:20231106T113000
DTSTAMP:20260504T175911
CREATED:20240222T071857Z
LAST-MODIFIED:20240222T152725Z
UID:10002788-1699266600-1699270200@cmsa.fas.harvard.edu
SUMMARY:Deformations of Landau-Ginzburg models and their fibers
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Andrew Harder\, Lehigh University \nTitle: Deformations of Landau-Ginzburg models and their fibers \nAbstract: In mirror symmetry\, the dual object to a Fano variety is a Landau-Ginzburg model. Broadly\, a Landau-Ginzburg model is quasi-projective variety Y with a superpotential function w\, but not all such pairs correspond to Fano varieties under mirror symmetry\, so a very natural question to ask is: Which Landau-Ginzburg models are mirror to Fano varieties? In this talk\, I will discuss a cohomological characterization of mirrors of (semi-)Fano varieties\, focusing on the case of threefolds. I’ll discuss how this characterization relates to the deformation and Hodge theory of (Y\,w)\, and in particular\, how the classification of (semi-)Fano threefolds is related to questions about moduli spaces of lattice polarized K3 surfaces.
URL:https://cmsa.fas.harvard.edu/event/agst-11623/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-11.06.2023.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231023T103000
DTEND;TZID=America/New_York:20231023T113000
DTSTAMP:20260504T175911
CREATED:20240222T073026Z
LAST-MODIFIED:20240222T073026Z
UID:10002789-1698057000-1698060600@cmsa.fas.harvard.edu
SUMMARY:Gauged Linear Sigma Models and Cohomological Field Theories
DESCRIPTION:Algebraic Geometry in String Theory Seminar \n\nSpeaker: David Favero\, University of Minnesota \n\nTitle: Gauged Linear Sigma Models and Cohomological Field Theories \nAbstract: This talk is dedicated to the memory of my friend and collaborator Bumsig Kim and based on joint work with Ciocan-Fontanine-Guere-Kim-Shoemaker.  Gauged Linear Sigma Models (GLSMs)  serve as a means of interpolating between Kahler geometry and singularity theory.  In enumerative geometry\, they should specialize to both Gromov-Witten and Fan-Jarvis-Ruan-Witten theory.   In joint work with Bumsig Kim (see arXiv:2006.12182)\, we constructed such enumerative invariants for GLSMs.  Furthermore\, we proved that these invariants form a Cohomological Field Theory.   In this lecture\, I will describe GLSMs and Cohomological Field Theories\, review the history of their development in enumerative geometry\, and discuss the construction of these general invariants.  Briefly\, the invariants are obtained by forming the analogue of a virtual fundamental class which lives in the twisted Hodge complex over a certain “moduli space of maps to the GLSM”.  This virtual fundamental class roughly comes as the Atiyah class of a “virtual matrix factorization” associated to the GLSM data.
URL:https://cmsa.fas.harvard.edu/event/agst-102323/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-10.23.2023.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231016T100000
DTEND;TZID=America/New_York:20231016T113000
DTSTAMP:20260504T175911
CREATED:20240222T075624Z
LAST-MODIFIED:20240222T075624Z
UID:10002790-1697450400-1697455800@cmsa.fas.harvard.edu
SUMMARY:Moduli of boundary polarized Calabi-Yau pairs
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nPre-talk Speaker: Rosie Shen (Harvard): 10:00-10:30 am \nPre-talk Title: Introduction to the singularities of the MMP \n\nSpeaker: Dori Bejleri (Harvard Math & CMSA) \nTitle: Moduli of boundary polarized Calabi-Yau pairs \nAbstract: The theories of KSBA stability and K-stability furnish compact moduli spaces of general type pairs and Fano pairs respectively. However\, much less is known about the moduli theory of Calabi-Yau pairs. In this talk I will present an approach to constructing a moduli space of Calabi-Yau pairs which should interpolate between KSBA and K-stable moduli via wall-crossing.  I will explain how this approach can be used to construct projective moduli spaces of plane curve pairs. This is based on joint work with K. Ascher\, H. Blum\, K. DeVleming\, G. Inchiostro\, Y. Liu\, X. Wang. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/agst-101623/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-10.16.2023.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230925T100000
DTEND;TZID=America/New_York:20230925T113000
DTSTAMP:20260504T175911
CREATED:20240222T090151Z
LAST-MODIFIED:20240222T090151Z
UID:10002792-1695636000-1695641400@cmsa.fas.harvard.edu
SUMMARY:Species Scale across String Moduli Spaces
DESCRIPTION:Algebraic Geometry in String Theory Seminar \n\nPre-talk Speaker: David Wu (Harvard Physics): 10:00-10:30 am \nSpeaker: Damian van de Heisteeg\, CMSA \n\nTitle: Species Scale across String Moduli Spaces \nAbstract: String theories feature a wide array of moduli spaces. We propose that the energy cutoff scale of these theories – the so-called species scale – can be determined through higher-curvature corrections. This species scale varies with the moduli; we use it both asymptotically to bound the diameter of the field space\, as well as in the interior to determine a “desert point” where it is maximized.
URL:https://cmsa.fas.harvard.edu/event/agst-92523/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
END:VEVENT
END:VCALENDAR