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X-WR-CALNAME:Laboratoire de Mathématiques de Versailles
X-ORIGINAL-URL:https://lmv.math.cnrs.fr
X-WR-CALDESC:Évènements pour Laboratoire de Mathématiques de Versailles
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TZID:Europe/Paris
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DTSTART:20250330T010000
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DTSTART:20260329T010000
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DTSTART:20261025T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260120T140000
DTEND;TZID=Europe/Paris:20260120T150000
DTSTAMP:20260521T082551
CREATED:20251128T163433Z
LAST-MODIFIED:20260123T131759Z
UID:14639-1768917600-1768921200@lmv.math.cnrs.fr
SUMMARY:AG : Gérard Freixas (CMLS) : Sur l’isomorphisme de Deligne-Riemann-Roch
DESCRIPTION:Résumé: Dans une lettre à Quillen datant des années 80\, Deligne a proposé un programme conjectural dont le but ultime est de relever la formule de Grothendieck-Riemann-Roch en degré 1\, en un isomorphisme de fibrés en droites\, avec une dépendance fonctorielle dans les données. Basé sur les travaux de Mumford sur les espaces de modules de courbes\, Deligne a traité le cas de dimension relative 1. Dans cet exposé\, je donnerai un aperçu du programme de Deligne\, et je présenterai un travail avec Dennis Eriksson\, dans lequel nous établissons un isomorphisme de Deligne-Riemann-Roch en général.
URL:https://lmv.math.cnrs.fr/evenenement/ag-gerard-freixas-cmls/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260127T133000
DTEND;TZID=Europe/Paris:20260127T143000
DTSTAMP:20260521T082551
CREATED:20260121T212242Z
LAST-MODIFIED:20260130T081503Z
UID:14720-1769520600-1769524200@lmv.math.cnrs.fr
SUMMARY:AG : Quang Khai Nguyen : Université Lyon 1 : Generating series of degree sequences in algebraic dynamics
DESCRIPTION:In algebraic dynamics\, we wish to understand the integer sequence given by the degrees of iterates of a dominant rational self-map. Typical examples include the Fibonacci sequence and other linear recurrence sequences\, though not all such degree sequences satisfy a finite recurrence. Their growth is captured by the dynamical degree\, an invariant governing the topological and arithmetic complexity of the dynamical system. I will present algebraic and analytic results concerning the generating series of these sequences in the toric setting\, including an affirmative answer to Jason Bell’s question on the transcendence of the reduction of these series modulo primes.
URL:https://lmv.math.cnrs.fr/evenenement/quang-khai-nguyen-universite-lyon-1-generating-series-of-degree-sequences-in-algebraic-dynamics/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260203T133000
DTEND;TZID=Europe/Paris:20260203T143000
DTSTAMP:20260521T082551
CREATED:20260125T161030Z
LAST-MODIFIED:20260203T160622Z
UID:14741-1770125400-1770129000@lmv.math.cnrs.fr
SUMMARY:AG : Mikhail Zaitsev : Proof of the KKLS conjecture on the mean value of the gl-weight system (HSE\, IHES)
DESCRIPTION:In my talk\, I will introduce several sets of central elements in the universal enveloping algebra U(gl_N) and explain the relationships between them using average value of the gl-weight system as an example. As a consequence\, we obtain a proof of the M.Kazarian\, E.Krasilnikov\, S.Lando\, and M.Shapiro conjecture that the mean value of the gl-weight system is a tau function of the KP hierarchy.
URL:https://lmv.math.cnrs.fr/evenenement/mikhail-zaitsev-proof-of-the-kkls-conjecture-on-the-mean-value-of-the-gl-weight-system/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260210T133000
DTEND;TZID=Europe/Paris:20260210T143000
DTSTAMP:20260521T082551
CREATED:20260205T093532Z
LAST-MODIFIED:20260213T083519Z
UID:14774-1770730200-1770733800@lmv.math.cnrs.fr
SUMMARY:AG : Florian Fürnsinn (Université de Vienne) : Galois Groups of D-finite Series modulo Primes
DESCRIPTION:Abstract: A D-finite series is a power series over the rational numbers that satisfies a linear differential equation with polynomial coefficients. Reducing a D-finite series modulo a prime number one often obtains an algebraic power series in positive characteristic. For diagonals of multivariate rational functions this was observed by Furstenberg in 1967\, and for hypergeometric functions this can be deduced from results by Christol\, and was made precise in recent work by Vargas-Montoya. In these cases\, one can consider the Galois group of the reduction over the field of rational functions. \nIn this talk\, I will showcase many examples of D-finite series of different nature for which we are (almost) able to compute said Galois groups for almost all prime numbers for which they are defined. Then\, I will collect these observations to raise questions on the general behavior of these groups: Is there some uniformity of the Galois groups with respect to the prime number\, and does there exist an object in characteristic zero governing their behavior\, like the differential Galois group of the minimal equation for the series? Much like the Grothendieck p-curvature conjecture\, we are looking for a local-global principle\, but we are concerned with only a single solution of a differential equation\, instead of a full basis. \nThis talk is based on joint work with X. Caruso and D. Vargas-Montoya.
URL:https://lmv.math.cnrs.fr/evenenement/ag-florian-furnsinn-universite-de-vienne/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260217T133000
DTEND;TZID=Europe/Paris:20260217T150000
DTSTAMP:20260521T082551
CREATED:20260122T134356Z
LAST-MODIFIED:20260220T084240Z
UID:14729-1771335000-1771340400@lmv.math.cnrs.fr
SUMMARY:AG : Pierre-Guy Plamondon (LMV) : Représentations\, amas et espaces de configurations
DESCRIPTION:Résumé : Je vais expliquer comment les algèbres amassées\, puis la théorie des représentations\, peuvent servir pour réaliser certains espaces de configurations.  Je me concentrerai sur l’espace \(M_{0\,n}\) des configurations de n points distincts sur la droite projective\, qui est lié à la théorie des représentations d’un carquois de type Dynkin \(A_{n-3}\). Si le temps le permet\, je parlerai de résultats obtenus dans cette direction avec Arkani-Hamed\, Frost\, Salvatori et Thomas.
URL:https://lmv.math.cnrs.fr/evenenement/ag-pierre-guy-plamondon-lmv-2/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260317T133000
DTEND;TZID=Europe/Paris:20260317T143000
DTSTAMP:20260521T082551
CREATED:20260121T212551Z
LAST-MODIFIED:20260319T110212Z
UID:14722-1773754200-1773757800@lmv.math.cnrs.fr
SUMMARY:AG : Trung Nghiem : Université Lyon 1 : Une construction effective des variétés de Calabi–Yau asymptotiquement coniques
DESCRIPTION:Une métrique asymptotiquement conique de Calabi–Yau est une métrique kählérienne à courbure de Ricci nulle\, dont l’allure à l’infini ressemble à un cône de Calabi–Yau. Un travail récent de Conlon–Hein montre qu’une variété AC de Calabi–Yau à cône asymptotique donné est obtenue soit par déformation\, soit par désingularisation crépante du cône. En fonction de la métrique sur le cône\, la variété AC est dite quasi-régulière ou irrégulière. Les exemples du dernier sont notamment rares dans la littérature et relativement beaucoup moins faciles à construire que les exemples quasi-réguliers. Dans mon exposé\, je vais présenter une stratégie effective pour construire des variétés non-compactes de Calabi–Yau irrégulières via la théorie d’Altmann sur les déformations des cônes toriques de Calabi–Yau. Il s’agit d’un travail en commun avec Ronan J. Conlon (University of Texas\, Dallas).
URL:https://lmv.math.cnrs.fr/evenenement/trung-nghiem-universite-lyon-1/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260324T133000
DTEND;TZID=Europe/Paris:20260324T143000
DTSTAMP:20260521T082551
CREATED:20260315T174427Z
LAST-MODIFIED:20260327T131156Z
UID:14871-1774359000-1774362600@lmv.math.cnrs.fr
SUMMARY:AG : Lucas Gerth (Jussieu) : Moduli spaces of analytic p-divisible groups.
DESCRIPTION:Abstract: We prove a classification of families of analytic p-divisible groups on adic spaces S over Qp in terms of Hodge–Tate triples on S\, generalizing a theorem of Fargues. From this\, for S a perfectoid space\, we construct an analytic Dieudonné theory with values in mixed characteristic Shtukas over the Fargues–Fontaine disc. As applications\, we realize the local Shimura varieties of EL and PEL type of Scholze–Weinstein as moduli spaces of analytic p-divisible groups with framed universal cover\, and we reinterpret the Hodge–Tate period map of Scholze in terms of topologically p-torsion subgroups of abelian varieties.
URL:https://lmv.math.cnrs.fr/evenenement/ag-lucas-gerth-jussieu/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260414T133000
DTEND;TZID=Europe/Paris:20260414T143000
DTSTAMP:20260521T082551
CREATED:20260402T130306Z
LAST-MODIFIED:20260417T082256Z
UID:14895-1776173400-1776177000@lmv.math.cnrs.fr
SUMMARY:AG : Alexander Stadler (University of Vienna) : Combinatorics of Extended Multi-Segments
DESCRIPTION:Abstract: Let F be a p-adic field. We consider representations of Arthur type of a classical group G over F. By use of the Endoscopic Classification\, Moeglin gave an explicit way to construct Arthur packets when G is a symplectic or special orthogonal group. Further analysis by Xu and Atobe developed the notion of Extended Multi-Segments\, which parametrise certain Arthur packets. We review the definition\, the construction of these representations in terms of Langlands data and consider some combinatorial problems that arise in this context.
URL:https://lmv.math.cnrs.fr/evenenement/ag-alexander-stadler/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260505T133000
DTEND;TZID=Europe/Paris:20260505T140000
DTSTAMP:20260521T082551
CREATED:20260430T161305Z
LAST-MODIFIED:20260507T114022Z
UID:15005-1777987800-1777989600@lmv.math.cnrs.fr
SUMMARY:AG : Lucas Pannier (LMV) : An effective proof of the p-curvature conjecture for first-order differential equations with rational coefficients
DESCRIPTION:Abstract: In 1974\, Honda proved the p-curvature conjecture for order one differential equations with rational coefficients over a number field. He demonstrated that in this setting\, the p-curvature conjecture was equivalent to a theorem due to Kronecker\, providing a local-global criterion for the splitting of polynomials over the rational numbers. In 1985 the Chudnovskys published another proof of Honda’s theorem (and of Kronecker’s theorem) by means of Padé approximation and elementary number theory\, thus paving the way to an effective version of these results. Here\, by « effective » we mean that we wish to obtain an explicit finite bound on the number of p-curvatures to be computed in order to decide the algebraicity of the solution of the differential equation. \nIn this talk\, I will explain how to obtain such a bound. \nThis is joint work with Florian Fürnsinn (University of Vienna).
URL:https://lmv.math.cnrs.fr/evenenement/ag-lucas-pannier-lmv-an-effective-proof-of-the-p-curvature-conjecture-for-first-order-differential-equations-with-rational-coefficients/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260505T140000
DTEND;TZID=Europe/Paris:20260505T143000
DTSTAMP:20260521T082551
CREATED:20260430T161917Z
LAST-MODIFIED:20260507T114028Z
UID:15007-1777989600-1777991400@lmv.math.cnrs.fr
SUMMARY:AG : Davide Ricci (LMV) : The Mori cone of certain Hassett spaces
DESCRIPTION:Abstract: The talk will introduce the F-conjecture\, which states that the Mori cone of the moduli space of genus g stable curves ‾Mg\,n is generated by 1-dimensional strata. We will see that the question can be formulated on any Hassett space and has a positive answer when the universal family is a P1-bundle. In particular\, we review how these particular Hassett spaces are naturally isomorphic to certain GIT quotients (P1)n // PGL2\, and we characterize these spaces as the targets of the birational contractions of Bln-1Pn-3 with Q-factorial image.
URL:https://lmv.math.cnrs.fr/evenenement/ag-davide-ricci-lmv-the-mori-cone-of-certain-hassett-spaces/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260519T133000
DTEND;TZID=Europe/Paris:20260519T143000
DTSTAMP:20260521T082551
CREATED:20260302T163943Z
LAST-MODIFIED:20260514T073238Z
UID:14829-1779197400-1779201000@lmv.math.cnrs.fr
SUMMARY:AG : Bernhard Keller (Université Paris Cité) : Catégorification du tressage grassmannien
DESCRIPTION:Résumé : En 2017\, Chris Fraser a découvert une action du groupe de tresses affine étendu à d brins sur la (grosse cellule de la) grassmannienne des sous-espaces de dimension k d’un espace de dimension n\, munie de sa structure d’algèbre amassée (cluster) due à Scott (2006). Ici\, l’entier d désigne le plus grand commun diviseur de k et n. Nous construisons un relèvement catégorique de cette action en utilisant la catégorification (additive) de la grassmannienne par Jensen\, King et Su via les modules de Cohen–Macaulay gradués sur une singularité de courbe plane. Un ingrédient essentiel est l’action du groupe de tresses de Seidel et Thomas (2000) sur la catégorie dérivée d’une algèbre de Calabi–Yau. Cet exposé est basé sur la thèse de doctorat en cours de Haoyu Wang.
URL:https://lmv.math.cnrs.fr/evenenement/ag-bernhard-keller-imj-prg/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260526T133000
DTEND;TZID=Europe/Paris:20260526T143000
DTSTAMP:20260521T082551
CREATED:20260305T161023Z
LAST-MODIFIED:20260305T161023Z
UID:14833-1779802200-1779805800@lmv.math.cnrs.fr
SUMMARY:AG : Sophie Morier-Genoud (Université de Reims)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-sophie-morier-genoud-universite-de-reims/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260609T133000
DTEND;TZID=Europe/Paris:20260609T143000
DTSTAMP:20260521T082551
CREATED:20260304T131807Z
LAST-MODIFIED:20260304T131807Z
UID:14831-1781011800-1781015400@lmv.math.cnrs.fr
SUMMARY:AG : Baptiste Rognerud (IMJ-PRG)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-baptiste-rognerud-imj-prg-2/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260616T133000
DTEND;TZID=Europe/Paris:20260616T143000
DTSTAMP:20260521T082551
CREATED:20260403T085232Z
LAST-MODIFIED:20260403T085232Z
UID:14899-1781616600-1781620200@lmv.math.cnrs.fr
SUMMARY:AG : Jeremy Lovejoy (CNRS\, Université Paris Cité)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-jeremy-lovejoy-cnrs-universite-paris-cite/
CATEGORIES:Séminaire AG
END:VEVENT
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