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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230124T160000
DTEND;TZID=Europe/Berlin:20230124T170000
DTSTAMP:20260531T235844
CREATED:20221108T131957Z
LAST-MODIFIED:20230113T083616Z
UID:4212-1674576000-1674579600@crc326gaus.de
SUMMARY:Slope of Siegel modular forms: some geometric applications
DESCRIPTION:International Seminar on Automorphic Forms \nWe study the slope of modular forms on the Siegel space. We will recover known divisors of  minimal slope for $g\leq5$ and we discuss the Kodaira dimension of the moduli space of principally polarized abelian varieties $A_g$ (and eventually of the generalized Kuga’s varieties). Moreover we illustrate the cone of moving divisors on $A_g$. Partly motivated by the generalized Rankin-Cohen bracket\, we construct a non-linear holomorphic differential operator that sends Siegel modular forms to Siegel cusp forms\, and we apply it to produce new modular forms. Our construction recovers the known divisors of minimal moving slope on $A_g$ for $g\leq5$. \nRiccardo Salvati Manni (Sapienza University of Rome) \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/international-seminar-on-automorphic-forms-tba-9/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230127T133000
DTEND;TZID=Europe/Berlin:20230127T150000
DTSTAMP:20260531T235844
CREATED:20230118T155149Z
LAST-MODIFIED:20230124T142517Z
UID:4758-1674826200-1674831600@crc326gaus.de
SUMMARY:Automorphisms of categories of schemes
DESCRIPTION:Remy van Dobben de Bruyn (Universität Utrecht) \nAbstract: Given two schemes S and S’\, we show that any equivalence between Sch/S and Sch/S’ comes from a unique isomorphism between S and S’. In particular\, the category of schemes does not have any nontrivial automorphisms. This eliminates all Noetherian and finite type hypotheses from a result of Mochizuki\, and answers a series of questions of Brandenburg. The methods are analogous to those in anabelian geometry (but easier)\, and this talk also serves as an introduction to those ideas for non-experts. \n 
URL:https://crc326gaus.de/event/automorphisms-of-categories-of-schemes/
LOCATION:Heidelberg\, Mathematikon\, SR A and Livestream
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Christian Dahlhausen":MAILTO:cdahlhausen@mathi.uni-heidelberg.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230127T153000
DTEND;TZID=Europe/Berlin:20230127T170000
DTSTAMP:20260531T235844
CREATED:20230124T110110Z
LAST-MODIFIED:20230124T114322Z
UID:4781-1674833400-1674838800@crc326gaus.de
SUMMARY:Motives of moduli of bundles on curves
DESCRIPTION:Seminar Arithmetic Geometry \nSimon Pepin Lehalleur (Radboud-Universiteit Nijmegen) \nAbstract: (Joint with Victoria Hoskins\, Nijmegen) Moduli spaces and stacks of bundles on smooth projective curves are basic objects of algebraic geometry and part of the geometric set-up of the Langlands program for function fields. Their cohomology is well understood in some ways and still very mysterious in others. After some recollections on Voevodsky\nmotives\, I will present several results about the motives of the moduli stack of vector bundles and the moduli spaces of semistable Higgs bundles\, expressing them in terms of the motives of powers of the base curve. I will then explain how this can combined with constructions of Maulik-Shen to prove a motivic version of the “topological mirror symmetry” connecting moduli spaces of SL_n and PGL_n-Higgs bundles. \nZoom (Meeting-ID: 635 7328 0984\, Password: smallest six digit prime) \n 
URL:https://crc326gaus.de/event/motives-of-moduli-of-bundles-on-curves/
LOCATION:Darmstadt\, Room 401 and Zoom\, Schlossgartenstraße 7\, Darmstadt\, 64289\, Germany
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230131T160000
DTEND;TZID=Europe/Berlin:20230131T170000
DTSTAMP:20260531T235844
CREATED:20221108T132141Z
LAST-MODIFIED:20230124T083330Z
UID:4214-1675180800-1675184400@crc326gaus.de
SUMMARY:Continuity and value distribution of quantum modular forms
DESCRIPTION:International Seminar on Automorphic Forms \nSandro Bettin (University of Genova) \nQuantum modular forms are functions f defined on the rationals whose period functions\, such as ψ(x):= f(x) – x-k f(-1/x) (for level 1)\, satisfy some continuity properties. In the case of k=0\, f can be interpreted as a Birkhoff sums associated with the Gauss map. In particular\, under mild hypotheses on G\, one can show convergence to a stable law. If k is non-zero\, the situation is rather different and we can show that mild conditions on psi imply that f itself has to exhibit some continuity property. Finally\, we discuss the convergence in distribution also in this case. This is a joint work with Sary Drappeau. \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/international-seminar-on-automorphic-forms-tba-10/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230202T140000
DTEND;TZID=Europe/Berlin:20230202T160000
DTSTAMP:20260531T235844
CREATED:20221116T085643Z
LAST-MODIFIED:20230116T081424Z
UID:4326-1675346400-1675353600@crc326gaus.de
SUMMARY:Toroidal b-divisors and applications in differential and arithmetic geometry
DESCRIPTION:Ana Botero (Regensburg) \nWe define toroidal b-divisors on a quasi projective variety over a field. These can be seen as conical functions on a balanced polyhedral space. We show the existence of an intersection pairing for so called nef toroidal b-divisors\, which gives rise to a Monge-Ampére type measure on the polyhedral space. Moreover\, using the theory of Okounkov bodies\, we show that a Hilbert-Samuel type formula holds in this setting. We then show some applications of this theory. First\, we show some Chern-Weil type formulae for singular semi-positive metrics on line bundles. Then\, using the Hilbert-Samuel formula\, we compute asymptotic dimension formulae of spaces of automorphic forms on mixed Shimura varieties.
URL:https://crc326gaus.de/event/tba-30/
LOCATION:Mainz\, Hilbertraum (05-432)
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230203T133000
DTEND;TZID=Europe/Berlin:20230203T150000
DTSTAMP:20260531T235844
CREATED:20221214T130418Z
LAST-MODIFIED:20221214T130418Z
UID:4629-1675431000-1675436400@crc326gaus.de
SUMMARY:Integrality of smoothed p-adic Artin L-functions
DESCRIPTION:Bence Forrás (Universität Duisburg-Essen) \nAbstract: We introduce a smoothed version of the equivariant S-truncated p-adic Artin L-function for one-dimensional admissible p-adic Lie extensions of number fields. Integrality of this smoothed p-adic L-function\, conjectured by Greenberg\, has been verified for pro-p extensions (assuming the Equivariant Iwasawa Main Conjecture) as well as p-abelian extensions (unconditionally). Integrality in the general case is also expected to hold\, and is the subject of ongoing research.
URL:https://crc326gaus.de/event/integrality-of-smoothed-p-adic-artin-l-functions/
LOCATION:Heidelberg\, Mathematikon\, SR A and Livestream
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230203T140000
DTEND;TZID=Europe/Berlin:20230203T150000
DTSTAMP:20260531T235844
CREATED:20221205T120737Z
LAST-MODIFIED:20230123T134644Z
UID:4484-1675432800-1675436400@crc326gaus.de
SUMMARY:Linear degenerate tropical flag matroids
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (Second meeting Winter Semester 2022/23) \nVictoria Schleis (Universität Tübingen) \nAbstract: Grassmannians and flag varieties are important moduli spaces in algebraic geometry. Their linear degenerations arise in representation theory as they describe quiver representations and their irreducible modules. As linear degenerations of flag varieties are difficult to analyze algebraically\, we describe them in a combinatorial setting and further investigate their tropical counterparts. \nIn this talk\, I will introduce matroidal\, polyhedral and tropical analoga and descriptions of linear degenerate flags and their varieties obtained in joint work with Alessio Borzì. To this end\, we introduce and study morphisms of valuated matroids. Using techniques from matroid theory\, polyhedral geometry and linear tropical geometry\, we use the correspondences between the different descriptions to gain insight on the structure of linear degeneration. Further\, we analyze the structure of linear degenerate flag varieties in all three settings\, and provide some cover relations on the poset of degenerations. For small examples\, we relate the observations on cover relations to the flat irreducible locus studied in representation theory.
URL:https://crc326gaus.de/event/tba-32/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230203T153000
DTEND;TZID=Europe/Berlin:20230203T163000
DTSTAMP:20260531T235844
CREATED:20221205T120951Z
LAST-MODIFIED:20230125T132340Z
UID:4496-1675438200-1675441800@crc326gaus.de
SUMMARY:Polyhedral models for K-theory
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (Second meeting Winter Semester 2022/23) \nLeonid Monin (Universität Leipzig) \nAbstract: One can associate a commutative\, graded algebra which satisfies Poincare duality to a homogeneous polynomial f on a vector space V. One particularly interesting example of this construction is when f is the volume polynomial on a suitable space of (virtual) polytopes. In this case the algebra A_f recovers cohomology rings of toric or flag varieties. \nIn my talk I will explain these results and present their recent generalizations. In particular\, I will explain how to associate an algebra with Gorenstein duality to any function g on a lattice L. In the case when g is the Ehrhart function on a lattice of integer (virtual) polytopes\, this construction recovers K-theory of toric and full flag varieties.
URL:https://crc326gaus.de/event/tba-33/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230203T164500
DTEND;TZID=Europe/Berlin:20230203T174500
DTSTAMP:20260531T235844
CREATED:20221205T121408Z
LAST-MODIFIED:20230124T140817Z
UID:4503-1675442700-1675446300@crc326gaus.de
SUMMARY:Universality for tropical maps
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (Second meeting Winter Semester 2022/23) \nNavid Nabijou (University of Cambridge) \nAbstract: I will discuss recent work concerning maps from tropical curves to orthants. A “combinatorial type” of such map is the data of an abstract graph together with slope vectors along the edges. To each such combinatorial type there is an associated moduli space\, which parametrises metric enhancements of the graph compatible with the given slopes. This moduli space is a rational polyhedral cone\, giving rise to an affine toric variety.\nOur main result shows that every rational polyhedral cone appears as the moduli space associated to some combinatorial type of tropical map. This establishes universality (also known as Murphy’s law) for tropical maps. The proof is constructive and extremely concrete\, as I will demonstrate. Combined with insights from logarithmic geometry\, our result implies that every toric singularity appears as a virtual singularity on a moduli space of stable logarithmic maps. \n\n\nThis is joint work with Gabriel Corrigan and Dan Simms.
URL:https://crc326gaus.de/event/tba-34/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230206T150000
DTEND;TZID=Europe/Berlin:20230206T173000
DTSTAMP:20260531T235844
CREATED:20230131T145759Z
LAST-MODIFIED:20230201T124708Z
UID:4821-1675695600-1675704600@crc326gaus.de
SUMMARY:The geometry of coherent sheaves: From derived categories to Higgs bundles
DESCRIPTION:GAUS-Workshop: “Invariants and curve counting” \n15:00-16:00: Luca Battistella (Frankfurt):\nLogarithmic and orbifold Gromov-Witten invariants\nAbstract: Logarithmic Gromov-Witten theory can be thought of as the study of curves in open manifolds\, or\, in other words\, curves with tangency conditions to a boundary divisor. When the divisor is smooth\, several techniques have been developed to compute the invariants\, most notably orbifold stable maps. When the divisor is normal crossings\, on the other hand\, the logarithmic theory remains hardly accessible. The strategy of rank reduction\, i.e. looking at the components of the boundary one at a time\, is more directly applicable to other theories than the logarithmic one (as shown in Nabijou-Ranganathan and B.-Nabijou-Tseng-You) due to tropical obstructions. Inspired by one of the distinguishing features of the logarithmic theory – namely\, birational invariance [Abramovich-Wise] – in joint work with Nabijou and Ranganathan we show that\, when the genus is zero\, tropical obstructions can be disposed of by blowing up the target sufficiently. The slogan is that the logarithmic theory is the limit orbifold theory under birational modifications along the boundary divisor. If time permits I will discuss work in progress towards understanding negative contact. \n16:20-17:20: Georg Oberdieck (Stockholm):\nPandharipande-Thomas theory of elliptic threefolds and Jacobi forms\nAbstract: Pandharipande-Thomas theory is the study of the intersection theory of the moduli space of stable pairs of a threefold. The intersection numbers\, called Pandharipande-Thomas invariants\, may be viewed as counting curves on the threefold subject to given incidence conditions. In this talk we explore the properties of the generating series of Pandharipande-Thomas invariants of elliptically fibered threefolds. There will be two main conjectures: Quasi-Jacobi Property and Holomorphic Anomaly Equations. Together these essentially determine the modular properties of the generating series. The conjectures are motivated by the case of Calabi-Yau threefolds where by mirror symmetry computations Huang-Katz-Klemm conjectured that the series of PT invariants are Jacobi forms. I discuss several examples\, in particular the equivariant geometry of K3xA^1. Here the conjectures lead to explicit new formulas for the invariants. Based on joint work with Maximilian Schimpf.
URL:https://crc326gaus.de/event/invariants-and-curve-counting/
LOCATION:Frankfurt\, Hilbertraum\, Rober-Mayer-Str. 6-8\, Raum 302
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230207T160000
DTEND;TZID=Europe/Berlin:20230207T170000
DTSTAMP:20260531T235844
CREATED:20221108T132317Z
LAST-MODIFIED:20230130T121438Z
UID:4216-1675785600-1675789200@crc326gaus.de
SUMMARY:Asymptotic equidistribution for partition statistics and topological invariants
DESCRIPTION:International Seminar on Automorphic Forms \nThroughout mathematics\, the equidistribution properties of certain objects are a central  theme studied by many authors. In my talk I am going to speak about a joint project with William Craig and Joshua Males\, where we provide a general framework for proving asymptotic equidistribution\, convexity\, and log-concavity of coefficients of generating functions on arithmetic progressions. \nGiulia Cesana (University of Cologne) \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/international-seminar-on-automorphic-forms-tba-11/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230210T153000
DTEND;TZID=Europe/Berlin:20230210T170000
DTSTAMP:20260531T235844
CREATED:20230130T121955Z
LAST-MODIFIED:20230130T121955Z
UID:4814-1676043000-1676048400@crc326gaus.de
SUMMARY:Revisiting derived crystalline cohomology
DESCRIPTION:Seminar Arithmetic Geometry \nZhouhang Mao (Paris) \nProjectively generated ∞-categories and left derived functors turn out to be important in derived geometry. In this talk\, we will present the result of the ∞-category of surjections  of animated rings being projectively generated\, the notion of animated PD-pairs —  surjections of animated rings with a “derived” PD-structure\, and how to use these tools to study the crystalline and prismatic cohomology. In particular\, we will deduce various comparison theorems without finiteness conditions. \nZoom (Meeting-ID: 635 7328 0984\, Password: smallest six digit prime)
URL:https://crc326gaus.de/event/revisiting-derived-crystalline-cohomology/
LOCATION:Darmstadt\, Room 401 and Zoom\, Schlossgartenstraße 7\, Darmstadt\, 64289\, Germany
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230414T080000
DTEND;TZID=Europe/Berlin:20230414T170000
DTSTAMP:20260531T235844
CREATED:20230414T122725Z
LAST-MODIFIED:20230414T122725Z
UID:5391-1681459200-1681491600@crc326gaus.de
SUMMARY:tba
DESCRIPTION:International Seminar on Automorphic Forms \nSachi Hashimoto (MPI Leipzig) \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/tba-39/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230418T140000
DTEND;TZID=Europe/Berlin:20230418T160000
DTSTAMP:20260531T235844
CREATED:20230419T123404Z
LAST-MODIFIED:20230427T143237Z
UID:5568-1681826400-1681833600@crc326gaus.de
SUMMARY:Arithmetic theta series from CM cycles
DESCRIPTION:Seminar: Non-archimedean geometry \nLucas Gerth (Universität Frankfurt) \nAbstract: We study arithmetic analogues of theta series. Given a simplectic vector space V and a Schwartz function f on V\, there is a collection of cycles Z(n\,f)\, consisting of CM points\, on the Siegel modular variety. Assuming that f satisfies a strong regular semisimple condition at some prime p\, we show that the generating series of the degrees of the cycles Z(n\,f) is a modular form\, We identify it explicitly with a classical theta series for a quaternion unitary similitude group. The proof relies on the p-adic uniformization of the supersingular locus on the Siegel modular variety.
URL:https://crc326gaus.de/event/arithmetic-theta-series-from-cm-cycles/
LOCATION:Frankfurt\, Robert-Mayer-Str. 6-8\, Raum 308
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Annette Werner":MAILTO:werner[at]math.uni-frankfurt.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230418T160000
DTEND;TZID=Europe/Berlin:20230418T170000
DTSTAMP:20260531T235844
CREATED:20230412T102513Z
LAST-MODIFIED:20230412T102513Z
UID:5367-1681833600-1681837200@crc326gaus.de
SUMMARY:On quasimodular forms associated to projective representations of symmetric groups
DESCRIPTION:International Seminar on Automorphic Forms \nWe explain how one can naturally associate a quasimodular form to a representation of a symmetric group. We determine its growth and explain how this construction is applied to several problems in enumerative geometry. Finally\, we discuss the difference between linear and projective representations. This is based on joint work with Adrien Sauvaget. \nJan-Willem van Ittersum (MPIM Bonn) \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/on-quasimodular-forms-associated-to-projective-representations-of-symmetric-groups/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230424T150000
DTEND;TZID=Europe/Berlin:20230424T173000
DTSTAMP:20260531T235844
CREATED:20230316T134050Z
LAST-MODIFIED:20230419T063337Z
UID:5090-1682348400-1682357400@crc326gaus.de
SUMMARY:The geometry of coherent sheaves: From derived categories to Higgs bundles
DESCRIPTION:GAUS-Workshop: “Recent developments in GIT” \n14:00-15:00: Victoria Hoskins (Nijmegen\, speaking remotely): An introduction to geometric invariant theory \nAbstract: The aim of this survey talk is to give an introduction to geometric invariant theory in order to prepare the audience for the subsequent talks as requested by the organisers. I will start by explaining how group actions often appear in moduli problems and we will see how constructing algebra-geometric quotients is related to 19th century invariant theory. I will explain why the theory is simplest for non-reductive group actions and\, in this case\, I will explain how Mumford constructs quotients (of certain open ‘semistable’ subsets) using geometric invariant theory\, as well as giving combinatorial and numerical criteria for semistability. If there is time\, I will briefly mention some recent developments to extend GIT to certain non-reductive group actions. \n15:20-16:20: Joshua Jackson (Sheffield): Advances in Non-reductive GIT and applications\n\nAbstract: Following from the previous talk on reductive GIT\, I will survey recent developments in extending this theory to non-reductive groups\, with a particular focus on applications to moduli theory. Time permitting\, I will then indicate how non-reductive GIT can be used in the study of sheaves\, Higgs bundles\, hypersurfaces\, and singular curves. \n16:40-17:40: Dario Weissmann (Essen): A stacky approach to identify the semi-stable locus of vector bundles \nAbstract: I report on recent joint work with Xucheng Zhang focusing on our Theorem A for vector bundles in characteristic 0: The semi-stable locus in the stack of bundles over a smooth projective curve is the maximal open locus admitting a schematic good moduli space. This gives an intrinsic motivation for semi-stability of vector bundles. Historically\, semi-stability appeared in the quest for a moduli space of bundles and the classical construction of this moduli space uses a non-canonical GIT-construction. Theorem A also provides us with natural examples of good moduli spaces which are only algebraic spaces and not schemes. \n 
URL:https://crc326gaus.de/event/the-geometry-of-coherent-sheaves-from-derived-categories-to-higgs-bundles-copy/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230425T140000
DTEND;TZID=Europe/Berlin:20230425T160000
DTSTAMP:20260531T235844
CREATED:20230419T123802Z
LAST-MODIFIED:20230425T104423Z
UID:5578-1682431200-1682438400@crc326gaus.de
SUMMARY:Comparison of tame and log-étale cohomology
DESCRIPTION:Seminar: Non-archimedean geometry\nCancelled: postponed by one week \nAmine Koubaa (Universität Frankfurt) \nAbstract: tba
URL:https://crc326gaus.de/event/tba-53/
LOCATION:Frankfurt\, Robert-Mayer-Str. 6-8\, Raum 308
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Annette Werner":MAILTO:werner[at]math.uni-frankfurt.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230425T160000
DTEND;TZID=Europe/Berlin:20230425T170000
DTSTAMP:20260531T235844
CREATED:20230414T122304Z
LAST-MODIFIED:20230418T130900Z
UID:5387-1682438400-1682442000@crc326gaus.de
SUMMARY:Almost holomorphic Drinfeld modular forms
DESCRIPTION:International Seminar on Automorphic Forms \nOguz Gezmis (Heidelberg University) \nIn his series of papers from 1970s\, Shimura analyzed a non-holomorphic operator\, nowadays called the Maass-Shimura operator\, and later extensively studied almost holomorphic modular forms. He also discovered their role on constructing class fields as well as the connection with periods of CM elliptic curves. In this talk\, our first goal is to introduce their positive characteristic counterpart\, almost holomorphic Drinfeld modular forms. We further relate them to Drinfeld quasi-modular forms which leads us to generalize the work of Bosser and Pellarin to a certain extend. Moreover\, we introduce the Maass-Shimura operator $\delta_k$ in our setting for any nonnegative integer k and investigate the relation between the periods of CM Drinfeld modules and the values at CM points of arithmetic Drinfeld modular forms under the image of $\delta_k$. If time permits\, we also reveal how to construct class fields by using such values. This is a joint work with Yen-Tsung Chen. \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/tba-37/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230502T140000
DTEND;TZID=Europe/Berlin:20230502T160000
DTSTAMP:20260531T235844
CREATED:20230419T124643Z
LAST-MODIFIED:20230427T143433Z
UID:5582-1683036000-1683043200@crc326gaus.de
SUMMARY:Gluing sheaves along Harder-Narasimhan strata of Bun_2
DESCRIPTION:Seminar: Non-archimedean geometry \nJonathan Miles (Universität Frankfurt) \nAbstract: We compute some examples of gluing sheaves on the moduli stack of rank 2 vector bundles on the Fargues-Fontaine curve. In the case of prime-to-p torsion coefficients\, the category D_ét(Bun_G) can be thought of as an approximation of the automorphic data appearing in the geometrization of the local Langlands correspondence due to Fargues-Scholze. The stratification of Bun_G arising from the Harder-Narasimhan slope formalism on G-isocrystals yields a semi-orthogonal decomposition of D_ét(Bun_G) into the derived categories of smooth representations of inner forms of Levi subgroups of G. Between such categories there is a full six functor formalism that can be used to compute how sheaves arising on a quasi-compact open substack interact with sheaves on higher strata via nearby cycles functors\, which can be interpreted as some derived analogue of Jacquet restriction functors for parabolic subgroups of G up to inner twisting. We restrict to G=GL_2 and to sufficiently nice coefficients (notably this includes an algebraic closure of F_\ell and Z/\ell^n Z for almost all \ell prime to p)\, and we will explain how these computations fundamentally reduce to the étale cohomology of local Shimura varieties (more generally local shtuka spaces).
URL:https://crc326gaus.de/event/tba-54/
LOCATION:Frankfurt\, Robert-Mayer-Str. 6-8\, Raum 308
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Annette Werner":MAILTO:werner[at]math.uni-frankfurt.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230502T160000
DTEND;TZID=Europe/Berlin:20230502T170000
DTSTAMP:20260531T235844
CREATED:20230414T122518Z
LAST-MODIFIED:20230418T115845Z
UID:5389-1683043200-1683046800@crc326gaus.de
SUMMARY:Mass equidistribution for Saito-Kurokawa lifts
DESCRIPTION:International Seminar on Automorphic Forms \nAbhishek Saha (Queen Mary University of London) \nThe Quantum Unique Ergodicity (QUE) conjecture was proved in the classical case for Maass forms of full level in the eigenvalue aspect by Lindenstrauss and Soundararajan\, and for holomorphic forms in the weight aspect by Holowinsky and Soundararajan. In this talk\, I will discuss some joint work with Jesse Jaasaari and Steve Lester on the analogue of the QUE conjecture in the weight aspect for holomorphic Siegel cusp forms of degree 2 and full level. Assuming the Generalized Riemann Hypothesis (GRH) we establish QUE for Saito–Kurokawa lifts as the weight tends to infinity. As an application\, we prove the equidistribution of zero divisors of Saito-Kurokawa lifts. \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/tba-38/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230504T141500
DTEND;TZID=Europe/Berlin:20230504T151500
DTSTAMP:20260531T235844
CREATED:20230321T081945Z
LAST-MODIFIED:20230427T120536Z
UID:5118-1683209700-1683213300@crc326gaus.de
SUMMARY:A p-Adic 6-Functor Formalism on Rigid-Analytic Varieties
DESCRIPTION:Lucas Mann (Münster) \nAbstract: Using Clausen-Scholze’s theory of condensed mathematics\, we construct a full 6-functor formalism for p-adic sheaves on rigid-analytic varieties. As a special case of this formalism we obtain Poincaré duality for the étale F_p-cohomology of smooth proper rigid-analytic varieties. By applying the formalism to classifying stacks of p-adic groups\, we obtain new insights into the p-adic Langlands program.
URL:https://crc326gaus.de/event/tba-31/
LOCATION:Mainz\, Hilbertraum (05-432)
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230505T133000
DTEND;TZID=Europe/Berlin:20230505T150000
DTSTAMP:20260531T235844
CREATED:20230428T094800Z
LAST-MODIFIED:20230428T095023Z
UID:5688-1683293400-1683298800@crc326gaus.de
SUMMARY:p-adic Gross--Zagier and rational points on modular curves
DESCRIPTION:Faltings’ theorem states that there are finitely many rational points on a nice projective curve defined over the rationals of genus at least 2. The quadratic Chabauty method makes explicit some cases of Faltings’ theorem. Quadratic Chabauty has recent notable success in determining the rational points of some modular curves. In this talk\, I will explain how we can leverage information from p-adic Gross–Zagier formulas to give a new quadratic Chabauty method for certain modular curves. Gross–Zagier formulas relate analytic quantities (special values of p-adic L-functions) to invariants of algebraic cycles (the p-adic height and logarithm of Heegner points). By using p-adic Gross–Zagier formulas\, this new quadratic Chabauty method makes essential use of modular forms to determine rational points.
URL:https://crc326gaus.de/event/p-adic-gross-zagier-and-rational-points-on-modular-curves/
LOCATION:Heidelberg\, Mathematikon\, SR A and Livestream
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Marius Leonhardt":MAILTO:mleonhardt@mathi.uni-heidelberg.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230505T140000
DTEND;TZID=Europe/Berlin:20230505T150000
DTSTAMP:20260531T235844
CREATED:20230417T120432Z
LAST-MODIFIED:20230419T065259Z
UID:5481-1683295200-1683298800@crc326gaus.de
SUMMARY:The SYZ conjecture for families of hypersurfaces
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (First meeting Summer Semester 2023) \nLéonard Pille-Schneider (ENS\, Paris) \nAbstract: Let X -> D* be a polarized family of complex Calabi-Yau manifolds\, whose complex structure degenerates in the worst possible way. The SYZ conjecture predicts that the fibers X_t\, as t ->0\, degenerate to a tropical object; and in particular the program of Kontsevich and Soibelman relates it to the Berkovich analytification of X\, viewed as a variety over the non-archimedean field of complex Laurent series.\nI will explain the ideas of this program and some recent progress in the case of hypersurfaces.
URL:https://crc326gaus.de/event/tba-50/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230505T153000
DTEND;TZID=Europe/Berlin:20230505T163000
DTSTAMP:20260531T235844
CREATED:20230417T120646Z
LAST-MODIFIED:20230510T075032Z
UID:5483-1683300600-1683304200@crc326gaus.de
SUMMARY:Tropical spin Hurwitz numbers
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (First meeting Summer Semester 2023) \nLou-Jean Cobigo (Universität Tübingen) \nAbstract: Classical Hurwitz numbers count the number of branched covers of a fixed target curve that exhibit a certain ramification behaviour. It is an enumerative problem deeply rooted in mathematical history.\nA modern twist: Spin Hurwitz numbers were introduced by Eskin-Okounkov-Pandharipande for certain computations in the moduli space of differentials on a Riemann surface.\nSimilarly to Hurwitz numbers they are defined as a weighted count of branched coverings of a smooth algebraic curve with fixed degree and branching profile. In addition\, they include information about the lift of a theta characteristic of fixed parity on the base curve. \nIn this talk we investigate them from a tropical point of view. We start by defining tropical spin Hurwitz numbers as result of an algebraic degeneration procedure\, but soon notice that these have a natural place in the tropical world as tropical covers with tropical theta characteristics on source and target curve.\nOur main results are two correspondence theorems stating the equality of the tropical spin Hurwitz number with the classical one.
URL:https://crc326gaus.de/event/tba-copy/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230505T164500
DTEND;TZID=Europe/Berlin:20230505T174500
DTSTAMP:20260531T235844
CREATED:20230403T131339Z
LAST-MODIFIED:20230418T125134Z
UID:5293-1683305100-1683308700@crc326gaus.de
SUMMARY:Tropical functions on skeletons: a finiteness result
DESCRIPTION:TGiF-Seminar: Tropical geometry in Frankfurt (First meeting Summer Semester 2023) \nAntoine Ducros (Sorbonne Université\, Paris) \nAbstract: Skeletons are subsets of non-archimedean spaces (in the sense of Berkovich) that inherit from the ambiant space a natural PL (piecewise-linear) structure\, and if S is such a skeleton\, for every invertible holomorphic function f defined in a neighborhood of S\, the restriction of log |f| to S is PL.\nIn this talk\, I will present a joint work with E.Hrushovski F. Loeser and J. Ye in which we consider an irreducible algebraic variety X over an algebraically closed\, non-trivially valued and complete non-archimedean field k\, and a skeleton S of the analytification of X defined using only algebraic functions\, and consisting of Zariski-generic points. If f is a non-zero rational function on X then log |f| induces a PL function on S\, and if we denote by E the group of all PL functions on S that are of this form\, we  prove the following finiteness result on the group E: it is stable under min and max\, and there exist finitely many non-zero rational functions f_1\,…f_m on X such that E is generated\, as a group equipped with min and max operators\, by the log |f_i| and the constants |a| for a in k^*. Our proof makes a crucial use of Hrushovski-Loeser’s model-theoretic approach of Berkovich spaces. \n 
URL:https://crc326gaus.de/event/tba-36/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230509T140000
DTEND;TZID=Europe/Berlin:20230509T160000
DTSTAMP:20260531T235844
CREATED:20230425T110303Z
LAST-MODIFIED:20230508T084428Z
UID:5619-1683640800-1683648000@crc326gaus.de
SUMMARY:Comparison of tame and log-étale cohomology
DESCRIPTION:Seminar: Non-archimedean geometry \nAmine Koubaa (Universität Frankfurt) \nAbstract:\nGiven a regular scheme $X$ and a normal crossing divisor $D$ one may concider two different cohomology groups.\nThe first one is the log étale cohomology developed by Illusie\, K. Kato and many others: We associate a logarithmic structure $M$ to $X$ and define the log étale site over $(X\,M)$.The second one is the tame cohomology developed by Hübner and Schmidt. Here we consider the tame site over the discretely ringed adic space $Spa(X\backslash D\,X)$. Tame morphisms are those which are étale and induce at most tamely ramified extension on the valuations.We construct a comparison morphism between these cohomology groups and prove that they are equal for schemes over $\mathbb{F}_p$ and locally constant finite sheaves once we assume resolution of singularities.“
URL:https://crc326gaus.de/event/comparison-of-tame-and-log-etale-cohomology-copy/
LOCATION:Frankfurt\, Robert-Mayer-Str. 6-8\, Raum 308
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Annette Werner":MAILTO:werner[at]math.uni-frankfurt.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230509T160000
DTEND;TZID=Europe/Berlin:20230509T170000
DTSTAMP:20260531T235844
CREATED:20230505T150422Z
LAST-MODIFIED:20230505T150422Z
UID:5750-1683648000-1683651600@crc326gaus.de
SUMMARY:p-adic Gross-Zagier and rational points on modular curves
DESCRIPTION:International Seminar on Automorphic Forms \nSachi Hashimoto (MPI Leipzig) \nFaltings’ theorem states that there are finitely many rational points on a nice projective curve defined over the rationals of genus at least 2. The quadratic Chabauty method makes explicit some cases of Faltings’ theorem. Quadratic Chabauty has recent notable success in determining the rational points of some modular curves. In this talk\, I will explain how we can leverage information from p-adic Gross-Zagier formulas to give a new quadratic Chabauty method for certain modular curves. Gross-Zagier formulas relate analytic quantities (special values of p-adic L-functions) to invariants of algebraic cycles (the p-adic height and logarithm of Heegner points). By using p-adic Gross-Zagier formulas\, this new quadratic Chabauty method makes essential use of modular forms to determine rational points.  \nYou can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736 \nThe password is the first Fourier coefficient of the modular j-function (as digits).
URL:https://crc326gaus.de/event/p-adic-gross-zagier-and-rational-points-on-modular-curves-2/
LOCATION:Zoom
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Claire Burrin":MAILTO:claire.burrin@math.uzh.ch
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230510T164500
DTEND;TZID=Europe/Berlin:20230510T180000
DTSTAMP:20260531T235844
CREATED:20230419T065010Z
LAST-MODIFIED:20231115T130317Z
UID:5557-1683737100-1683741600@crc326gaus.de
SUMMARY:Tropical perspectives in enumerative geometry
DESCRIPTION:Frankfurter Seminar – Kolloquium des Instituts für Mathematik \nRenzo Cavalieri (Colorado State University\, Fort Collins) \nAbstract: Enumerative geometry is an ancient branch of mathematics that aims to count the number of geometric objects that satisfy some constrains: the primordial enumerative geometric statement is that there is a unique straight line that passes through two distinct points in a plane. While enumerative geometric questions are often easy to state\, the attempts to answer them have both employed and spurred the development of several mathematical techniques.\nThis talk will be a broad and hopefully friendly survey of how tropical geometry has become an important actor for several enumerative problems especially related to counting curves. I will use Hurwitz theory as the running example\, and show how tropical geometry provides us not only with an interesting approach to classical Hurwitz theory\, but also allows us to define „new“ enumerative problems of Hurwitz type. Much of the work presented has been collaborative work with Paul Johnson\, Hannah Markwig\, Dhruv Ranganathan and Johannes Schmitt.
URL:https://crc326gaus.de/event/tropical-perspectives-in-enumerative-geometry/
LOCATION:Frankfurt\, Robert-Mayer-Str. 10\, Raum 711 groß
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230511T140000
DTEND;TZID=Europe/Berlin:20230511T160000
DTSTAMP:20260531T235844
CREATED:20230417T071727Z
LAST-MODIFIED:20230427T120413Z
UID:5436-1683813600-1683820800@crc326gaus.de
SUMMARY:Algebraicity and p-adic interpolation of critical Hecke L-values
DESCRIPTION:Johannes Sprang (Essen) \nAbstract: Euler’s beautiful formula on the values of the Riemann zeta function at the positive even integers can be seen as the starting point of the investigation of special values of L-functions. In particular\, Euler’s result shows that all critical zeta values are rational up to multiplication with a particular period\, here the period is a power of 2πi. Conjecturally this is expected to hold for all critical L-values of motives. In this talk\, I will explain a joint result with Guido Kings on the algebraicity of critical Hecke L-values up to explicit periods for totally imaginary fields. If time permits\, I will discuss the construction of p-adic L-functions for such fields as an application.
URL:https://crc326gaus.de/event/tba-48/
LOCATION:Mainz\, Hilbertraum (05-432)
CATEGORIES:GAUS-Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230512T133000
DTEND;TZID=Europe/Berlin:20230512T150000
DTSTAMP:20260531T235844
CREATED:20230505T131942Z
LAST-MODIFIED:20230505T131942Z
UID:5748-1683898200-1683903600@crc326gaus.de
SUMMARY:A quadratically refined tropical Bézout theorem
DESCRIPTION:Sabrina Pauli (Düsseldorf) \nAbstract: Results from motivic homotopy theory allow to study questions in enumerative geometry over an arbitrary field k. In this case the answer to these questions is not a number but a quadratic form carrying arithmetic information about the count. Using tropical geometry one can translate questions from enumerative geometry to questions in combinatorics which are often easier to solve. In my talk I will present one of the first examples of how to use tropical geometry for questions in enumerative geometry over an arbitrary field k\, namely a proof of Bézout’s theorem for tropical curves. This is joint work with Andrés Jaramillo Puentes. \n 
URL:https://crc326gaus.de/event/a-quadratically-refined-tropical-bezout-theorem/
LOCATION:Heidelberg\, Mathematikon\, SR A and Livestream
CATEGORIES:GAUS-Seminar
ORGANIZER;CN="Christian Dahlhausen":MAILTO:cdahlhausen@mathi.uni-heidelberg.de
END:VEVENT
END:VCALENDAR