BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Roberto Pignatelli (University of Trento) DTSTART:20200421T130000Z DTEND:20200421T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/1 DESCRIPTION:Title: Rigid compact complex surfaces that are not infinitesimally rigid\nb y Roberto Pignatelli (University of Trento) as part of Warwick algebraic g eometry seminar\n\n\nAbstract\nA complex manifold is rigid if every small deformation of its complex structure is trivial. The usual argument for pr oving the rigidity of a complex manifold is by a well known "standard" coh omological criterium. Morrow and Kodaira posed in 1971 the problem of cons tructing a rigid manifold that does not satisfy it. \n\nI will present a n ew criterium for rigidity of a manifold of dimension 2 that is more genera l than the standard one. As an application\, I will produce a family of ex amples satisfying our criterium and not the classical one\, so answering t he above question. \n\nThis is a joint work with I. Bauer.\n LOCATION:https://researchseminars.org/talk/WarwickAG/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Adam Gyenge (University of Oxford) DTSTART:20200428T130000Z DTEND:20200428T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/2 DESCRIPTION:Title: Hilbert and Quot schemes of simple surface singularities\nby Adam Gy enge (University of Oxford) as part of Warwick algebraic geometry seminar\ n\n\nAbstract\nThe Hilbert schemes of points on the affine complex plane h as the structure of a Nakajima quiver variety. For a finite subgroup G of SL(2\, C)\, I will discuss the construction of the Hilbert scheme of n poi nts on the Kleinian singularity C^2/G as a Nakajima quiver variety for the framed McKay quiver of G with a specific non-generic stability parameter. I will also present a formula for the generating series collecting the Eu ler numbers of these varieties\, a specific case of which was proved recen tly by Nakajima. Given enough time\, I will explain the analogous problem for certain Quot schemes of C^2/G. (Joint work with Alastair Craw\, Soren Gammelgaard and Balazs Szendroi).\n LOCATION:https://researchseminars.org/talk/WarwickAG/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Jean-Louis Colliot-Thélène (CNRS et Université Paris-Saclay) DTSTART:20200609T130000Z DTEND:20200609T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/3 DESCRIPTION:Title: On the integral Tate conjecture for 1-cycles on the product of a curve a nd a surface over a finite field\nby Jean-Louis Colliot-Thélène (CNR S et Université Paris-Saclay) as part of Warwick algebraic geometry semin ar\n\n\nAbstract\nLet X be the product of a smooth projective curve C and a smooth projective surface S over a finite field F. Assume the Chow group of zero-cycles on S is just Z over any algebraically closed field extensi on of F (example : Enriques surface). We give a simple condition on C and S which ensures that the integral Tate conjecture holds for 1-cycles on X. An equivalent formulation is a vanishing result for unramified cohomology of degree 3. This generalizes a result of A. Pirutka (2016). It is a join t work with Federico Scavia (UBC\, Vancouver).\n LOCATION:https://researchseminars.org/talk/WarwickAG/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Tyler Kelly (University of Birmingham) DTSTART:20200505T130000Z DTEND:20200505T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/4 DESCRIPTION:Title: A few aspects of hypergeometric functions in geometry and arithmetic \nby Tyler Kelly (University of Birmingham) as part of Warwick algebraic g eometry seminar\n\n\nAbstract\nHypergeometric functions are special functi ons that go back all the way to Euler and come all the way to Mirror Symme try\, Hodge theory\, and Gromov-Witten Theory. I plan to give a (very bias ed) stroll through some of their contexts/computations in algebraic geomet ry and Hodge theory\, and then explain the analogue of hypergeometric func tions over finite fields. This will then give us a way to organise point c ounts on certain varieties over finite fields. This talk will involve join t work with C Doran\, A Salerno\, S Sperber\, U Whitcher\, and J Voight.\n LOCATION:https://researchseminars.org/talk/WarwickAG/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Will Donovan (Yau MSC\, Tsinghua University) DTSTART:20200512T130000Z DTEND:20200512T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/5 DESCRIPTION:Title: Windows on the Pfaffian-Grassmannian correspondence\nby Will Donovan (Yau MSC\, Tsinghua University) as part of Warwick algebraic geometry sem inar\n\n\nAbstract\nThe Pfaffian-Grassmannian correspondence has been a ke y example in the development of Homological Projective Duality: it concern s certain pairs of non-birational Calabi-Yau threefolds which share a mirr or partner\, and can be proved to be derived equivalent. Physically\, such an equivalence is associated to B-brane transport along a path in a mirro r symmetry moduli space\, and is dependent on the homotopy class of that p ath: I give a mathematical implementation of this dependency\, in terms of mutations of an exceptional collection on the relevant Grassmannian. This follows a physical analysis of Hori and Eager-Hori-Knapp-Romo\, and build s on work with Addington and Segal.\n LOCATION:https://researchseminars.org/talk/WarwickAG/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Anthony Várilly-Alvarado (Rice University) DTSTART:20200519T130000Z DTEND:20200519T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/6 DESCRIPTION:Title: Quasi-hyperbolicity via explicit symmetric differentials\nby Anthony Várilly-Alvarado (Rice University) as part of Warwick algebraic geometry seminar\n\n\nAbstract\nA surface X is algebraically quasi-hyperbolic if i t contains finitely many curves of genus 0 or 1. In 2006\, Bogomolov and d e Oliveira used asymptotic computations to show that sufficiently nodal su rfaces of high degree in projective three-space carry symmetric differenti als\, and they used this to prove quasi-hyperbolicity of these surfaces. W e explain how a granular analysis of their ideas\, combined with computati onal tools and insights\, yield explicit results for the existence of symm etric differentials\, and we show how these results can be used to give co nstraints on the locus of rational curves on surfaces like the Barth Decic \, Buechi's surface\, and certain complete intersections of general type\, including the surface parametrizing perfect cuboids. This is joint work w ith Nils Bruin and Jordan Thomas.\n LOCATION:https://researchseminars.org/talk/WarwickAG/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Ana-Maria Castravet (Versailles) DTSTART:20200616T130000Z DTEND:20200616T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/8 DESCRIPTION:Title: Exceptional collections on moduli spaces of pointed stable rational curv es\nby Ana-Maria Castravet (Versailles) as part of Warwick algebraic g eometry seminar\n\n\nAbstract\nI will report on joint work with Jenia Teve lev answering a question of Orlov. We prove that the Grothendieck-Knudsen moduli spaces of pointed stable rational curves with n markings admit full \, exceptional collections that are invariant under the action of the symm etric group $S_n$ permuting the markings. In particular\, a consequence is that the K-group with integer coefficients is a permutation $S_n$-lattice .\n LOCATION:https://researchseminars.org/talk/WarwickAG/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Hans-Christian Graf von Bothmer (Hamburg) DTSTART:20200623T130000Z DTEND:20200623T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/9 DESCRIPTION:Title: Rigid\, not infinitesimally rigid surfaces with ample canonical bundle\nby Hans-Christian Graf von Bothmer (Hamburg) as part of Warwick algebr aic geometry seminar\n\n\nAbstract\nIt was a long-standing problem of Morr ow and Kodaira whether there are compact complex manifolds X with Def(X) a non reduced point. The first examples answering this question in the affi rmative were given by Bauer and Pignatelli in 2018. As explained by Robert o Pignatelli in this seminar some weeks ago\, these are certain surfaces o f general type that have nodal canonical models. These canonical models ar e rigid AND infinitesimally rigid\, while their desingularizations are sti ll rigid\, but not infinitesimally rigid anymore. One can therefore ask\, if this situation is typical for rigid\, not infinitesimally rigid surface s of general type\, or if it is possible to have examples with smooth cano nical models. We answer this question also in the affirmative by construct ing such a surface X via line arrangements and abelian covers. This constr uction was inspired by Vakil's version of „Murphy’s law in algebraic g eometry“. (This is joint work with Christian Böhning and Roberto Pignat elli.)\n LOCATION:https://researchseminars.org/talk/WarwickAG/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Enrica Mazzon (MPI Bonn) DTSTART:20200602T130000Z DTEND:20200602T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/10 DESCRIPTION:Title: Tropical affine manifolds from mirror symmetry to Berkovich geometry\nby Enrica Mazzon (MPI Bonn) as part of Warwick algebraic geometry semin ar\n\n\nAbstract\nMirror symmetry is a fast-moving research area at the bo undary between mathematics and theoretical physics. Originated from observ ations in string theory\, it suggests that certain geometrical objects (co mplex Calabi-Yau manifolds) should come in pairs\, in the sense that each of them has a mirror partner and the two share interesting geometrical pro perties. In this talk\, I will introduce some notions relating mirror symm etry to tropical geometry\, inspired by the work of Kontsevich-Soibelman a nd Gross-Siebert. In particular\, I will focus on the construction of a so -called “tropical affine manifold” using methods of non-archimedean ge ometry\, and the guiding example will be the case of K3 surfaces and some hyper-Kähler varieties. This is based on joint work with Morgan Brown and a work in progress with Léonard Pille-Schneider.\n LOCATION:https://researchseminars.org/talk/WarwickAG/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Michel van Garrel (Warwick) DTSTART:20200526T130000Z DTEND:20200526T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/11 DESCRIPTION:Title: Prelog Chow rings\nby Michel van Garrel (Warwick) as part of Warwic k algebraic geometry seminar\n\n\nAbstract\nIn this joint work with Christ ian Böhning and Hans-Christian Graf von Bothmer\, we explore Chow rings i n the setting of log geometry\, leading to the construction of prelog Chow rings of normal crossings varieties with smooth components. For a strictl y semistable degeneration\, the prelog Chow ring of the central fiber admi ts a specialization morphism from the Chow group of the generic fiber. Aft er introducing the definition\, I will describe examples illustration the construction.\n LOCATION:https://researchseminars.org/talk/WarwickAG/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Victor Batyrev (Tübingen) DTSTART:20200630T130000Z DTEND:20200630T140000Z DTSTAMP:20260422T191655Z UID:WarwickAG/12 DESCRIPTION:Title: Fine interior of lattice polytopes: MMP and Mirror Symmetry\nby Vic tor Batyrev (Tübingen) as part of Warwick algebraic geometry seminar\n\n\ nAbstract\nThe notion "Fine interior" of a lattice polytope P was introduc ed by Miles Reid in his famous lectures on canonical singularities. A non- degenerated hypersurface in a d-dimensional algebraic torus T is birationa l to a Calabi-Yau if and only if the Fine interior of its Newton polytope is a single lattice point. This is the starting point for my talk with the ambitious goal to explain my solutions to MMP and Mirror Symmetry for tor ic hypersurfaces.\n LOCATION:https://researchseminars.org/talk/WarwickAG/12/ END:VEVENT END:VCALENDAR