BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Ben Davison (Edinburgh) DTSTART:20201026T141500Z DTEND:20201026T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/1 DESCRIPTION:Title: C oproducts in the cohomological DT theory of 3-Calabi-Yau completions\n by Ben Davison (Edinburgh) as part of Oxford Geometry and Analysis Seminar \n\n\nAbstract\nGiven a suitably friendly category D we can take the 3-Cal abi Yau completion of D and obtain a 3-Calabi-Yau category E. The archetyp al example has D as the category of coherent sheaves on a smooth quasiproj ective surface\, then E is the category of coherent sheaves on the total s pace of the canonical bundle - a quasiprojective 3CY variety. The moduli s tack of semistable objects in the 3CY completion E supports a vanishing cy cle-type sheaf\, the hypercohomology of which is the basic object in the s tudy of the DT theory of E. Something extra happens when our input categor y is itself 2CY: examples include the category of local systems on a Riema nn surface\, the category of coherent sheaves on a K3/Abelian surface\, th e category of Higgs bundles on a smooth complete curve\, or the category o f representations of a preprojective algebra. In these cases\, the DT coho mology of E carries a cocommutative coproduct. I'll also explain how this interacts with older algebraic structures in cohomological DT theory to pr ovide a geometric construction of both well-known and new quantum groups.\ n LOCATION:https://researchseminars.org/talk/OxGeom/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Egor Shelukhin (Université de Montréal) DTSTART:20201102T141500Z DTEND:20201102T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/2 DESCRIPTION:Title: S mith theory in filtered Floer homology and Hamiltonian diffeomorphisms \nby Egor Shelukhin (Université de Montréal) as part of Oxford Geometry and Analysis Seminar\n\n\nAbstract\nWe describe how Smith theory applies i n the setting of Hamiltonian Floer homology filtered by the action functio nal\, and provide applications to questions regarding Hamiltonian diffeomo rphisms\, including the Hofer-Zehnder conjecture on the existence of infin itely many periodic points and a question of McDuff-Salamon on Hamiltonian diffeomorphisms of finite order.\n LOCATION:https://researchseminars.org/talk/OxGeom/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Davesh Maulik (MIT) DTSTART:20201109T141500Z DTEND:20201109T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/3 DESCRIPTION:Title: C ohomology of the moduli of Higgs bundles and the Hausel-Thaddeus conjectur e\nby Davesh Maulik (MIT) as part of Oxford Geometry and Analysis Semi nar\n\n\nAbstract\nIn this talk\, I will discuss some results on the struc ture of the cohomology of the moduli space of stable SL_n Higgs bundles on a curve. \nOne consequence is a new proof of the Hausel-Thaddeus conject ure proven previously by Groechenig-Wyss-Ziegler via p-adic integration.\n We will also discuss connections to the P=W conjecture if time permits. Ba sed on joint work with Junliang Shen.\n LOCATION:https://researchseminars.org/talk/OxGeom/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Mondino (Oxford) DTSTART:20201116T141500Z DTEND:20201116T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/4 DESCRIPTION:Title: O ptimal transport\, Ricci curvature lower bounds and group actions\nby Andrea Mondino (Oxford) as part of Oxford Geometry and Analysis Seminar\n\ n\nAbstract\nIn the talk I will survey the fast growing field of metric me asure spaces satisfying a lower bound on Ricci Curvature\, in a synthetic sense via optimal transport. Particular emphasis will be given to discuss how such (possibly non-smooth) spaces naturally (and usefully) extend the class of smooth Riemannian manifolds with Ricci curvature bounded below.\n LOCATION:https://researchseminars.org/talk/OxGeom/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Vidit Nanda (Oxford) DTSTART:20201123T141500Z DTEND:20201123T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/5 DESCRIPTION:Title: C omplex links and algebraic multiplicities\nby Vidit Nanda (Oxford) as part of Oxford Geometry and Analysis Seminar\n\n\nAbstract\nGiven a nested pair X and Y of complex projective varieties\, there is a single positive integer e which measures the singularity type of X inside Y. This is call ed the Hilbert-Samuel multiplicity of Y along X\, and it appears in the fo rmulations of several standard intersection-theoretic constructions includ ing Segre classes\, Euler obstructions\, and various other multiplicities. The standard method for computing e requires knowledge of the equations w hich define X and Y\, followed by a (super-exponential) Grobner basis comp utation. In this talk we will connect the HS multiplicity to complex links \, which are fundamental invariants of (complex analytic) Whitney stratifi ed spaces. Thanks to this connection\, the enormous computational burden o f extracting e from polynomial equations reduces to a simple exercise in c lustering point clouds. In fact\, one doesn't even need the polynomials wh ich define X and Y: it suffices to work with dense point samples. This is joint work with Martin Helmer.\n LOCATION:https://researchseminars.org/talk/OxGeom/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Soheyla Feyzbakhsh (Imperial) DTSTART:20201130T141500Z DTEND:20201130T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/6 DESCRIPTION:Title: A pplication of a Bogomolov-Gieseker type inequality to counting invariants< /a>\nby Soheyla Feyzbakhsh (Imperial) as part of Oxford Geometry and Analy sis Seminar\n\n\nAbstract\nIn this talk\, I will work on a smooth projecti ve threefold X which satisfies the Bogomolov-Gieseker conjecture of Bayer- Macrì-Toda\, such as the projective space P^3 or the quintic threefold. I will show certain moduli spaces of 2-dimensional torsion sheaves on X are smooth bundles over Hilbert schemes of ideal sheaves of curves and points in X. When X is Calabi-Yau this gives a simple wall crossing formula expr essing curve counts (and so ultimately Gromov-Witten invariants) in terms of counts of D4-D2-D0 branes. This is joint work with Richard Thomas.\n LOCATION:https://researchseminars.org/talk/OxGeom/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Dougal Davis (Edinburgh) DTSTART:20201207T110000Z DTEND:20201207T120000Z DTSTAMP:20260422T225755Z UID:OxGeom/7 DESCRIPTION:Title: T wo perspectives on the stack of principal bundles on an elliptic curve and its slices\nby Dougal Davis (Edinburgh) as part of Oxford Geometry an d Analysis Seminar\n\n\nAbstract\nLet G be a reductive group\, E an ellipt ic curve\, and Bun_G the moduli stack of principal G-bundles on E. In this talk\, I will attempt to explain why Bun_G is a very interesting object f rom the perspectives of both singularity theory on the one hand\, and shif ted symplectic geometry and representation theory on the other. In the fir st part of the talk\, I will explain how to construct slices of Bun_G thro ugh points corresponding to unstable bundles\, and how these are linked to certain singular algebraic surfaces and their deformations in the case of a "subregular" bundle. In the second (probably much shorter) part\, I wil l discuss the shifted symplectic geometry of Bun_G and its slices. If time permits\, I will sketch how (conjectural) quantisations of these structur es should be related to some well known algebras of an "elliptic" flavour\ , such as Sklyanin and Feigin-Odesskii algebras\, and elliptic quantum gro ups.\n LOCATION:https://researchseminars.org/talk/OxGeom/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Christian Ikenmeyer (University of Liverpool) DTSTART:20210118T141500Z DTEND:20210118T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/8 DESCRIPTION:Title: R epresentation theory in geometric complexity theory\nby Christian Iken meyer (University of Liverpool) as part of Oxford Geometry and Analysis Se minar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Guillem Cazassus (University of Oxford) DTSTART:20210125T141500Z DTEND:20210125T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/9 DESCRIPTION:Title: E quivariant Lagrangian Floer homology and Extended Field theory\nby Gui llem Cazassus (University of Oxford) as part of Oxford Geometry and Analys is Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Krzysztof Ciosmak (University of Oxford) DTSTART:20210201T141500Z DTEND:20210201T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/10 DESCRIPTION:Title: Leaf decompositions in Euclidean spaces\nby Krzysztof Ciosmak (Univers ity of Oxford) as part of Oxford Geometry and Analysis Seminar\n\n\nAbstra ct\nIn the talk I shall discuss an approach to the localisation technique\ , for spaces satisfying the curvature-dimension condition\, by means of L1 -optimal transport. Moreover\, I shall present recent work on a generalisa tion of the technique to multiple constraints setting. Applications of the theory lie in functional and geometric inequalities\, e.g. in the Lévy-G romov isoperimetric inequality.\n LOCATION:https://researchseminars.org/talk/OxGeom/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Dan Abramovich (Brown University) DTSTART:20210208T141500Z DTEND:20210208T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/11 DESCRIPTION:Title: Punctured invariants and gluing\nby Dan Abramovich (Brown University) as part of Oxford Geometry and Analysis Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Eckhard Meinrenken (University of Toronto) DTSTART:20210215T141500Z DTEND:20210215T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/12 DESCRIPTION:Title: Weightings and normal forms\nby Eckhard Meinrenken (University of Toro nto) as part of Oxford Geometry and Analysis Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Christian Bär (University of Potsdam) DTSTART:20210222T141500Z DTEND:20210222T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/13 DESCRIPTION:Title: Spaces of metrics of positive scalar curvature on manifolds with boundary< /a>\nby Christian Bär (University of Potsdam) as part of Oxford Geometry and Analysis Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Catherine Cannizzo (Stony Brook University) DTSTART:20210301T141500Z DTEND:20210301T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/14 DESCRIPTION:Title: Homological mirror symmetry for genus two curves\nby Catherine Cannizz o (Stony Brook University) as part of Oxford Geometry and Analysis Seminar \n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Diane MacLagan (University of Warwick) DTSTART:20210308T141500Z DTEND:20210308T151500Z DTSTAMP:20260422T225755Z UID:OxGeom/15 DESCRIPTION:Title: The spine of the T-graph of the Hilbert scheme\nby Diane MacLagan (Uni versity of Warwick) as part of Oxford Geometry and Analysis Seminar\n\nAbs tract: TBA\n LOCATION:https://researchseminars.org/talk/OxGeom/15/ END:VEVENT END:VCALENDAR