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X-WR-CALNAME:Département de mathématiques et applications
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X-WR-CALDESC:évènements pour Département de mathématiques et applications
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TZID:Europe/Paris
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20110327T010000
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TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20111030T010000
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TZNAME:CEST
DTSTART:20120325T010000
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DTSTART:20121028T010000
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DTSTART:20130331T010000
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DTSTART:20131027T010000
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END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131213T160000
DTEND;TZID=Europe/Paris:20131213T160000
DTSTAMP:20261028T033620
CREATED:20131213T150000Z
LAST-MODIFIED:20211104T094719Z
UID:8165-1386950400-1386950400@www.math.ens.psl.eu
SUMMARY:Non-archimedean Yomdin-Gromov parametrizations and points of bounded height
DESCRIPTION:In the spirit of work by Pila-Wilkie (2006) and by Pila (2009)\, we will present bounds on the number of points of bounded height in the non-archimedean context. An important tool to make the determinant method work is provided by a non-archimedean version of the Yomdin – Gromov parameterizing lemma. We wil explain these results\, obtained in joint work with G. Comte and F. Loeser.
URL:https://www.math.ens.psl.eu/evenement/non-archimedean-yomdin-gromov-parametrizations-and-points-of-bounded-height/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131213T141500
DTEND;TZID=Europe/Paris:20131213T141500
DTSTAMP:20261028T033620
CREATED:20131213T131500Z
LAST-MODIFIED:20211104T094759Z
UID:8166-1386944100-1386944100@www.math.ens.psl.eu
SUMMARY:Galois equations on torsion points and the Tate-Voloch conjecture on p-adic fields
DESCRIPTION:The Tate-Voloch conjecture is a statement about p-adic distance from torsion points to subvarieties in a semi-abelian variety defined over C_p. The use of Galois equations on torsion points by Pink and Rossler to prove the Manin-Mumford conjecture can be adapted to prove that conjecture in the case where both the semi-abelian variety and its subvariety are defined over a finite extension of Q_p.In this talk\, we will present such a proof\, and try to give an insight on how this proof differs from the model-theoretic one given by Scanlon.
URL:https://www.math.ens.psl.eu/evenement/galois-equations-on-torsion-points-and-the-tate-voloch-conjecture-on-p-adic-fields/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131213T110000
DTEND;TZID=Europe/Paris:20131213T110000
DTSTAMP:20261028T033620
CREATED:20131213T100000Z
LAST-MODIFIED:20211104T094759Z
UID:8167-1386932400-1386932400@www.math.ens.psl.eu
SUMMARY:Pregeometries and definable groups
DESCRIPTION:We describe a recent program for analyzing definable sets and groups in certain model theoretic settings. Those settings include:(a) o-minimal structures (M\, P)\, where M is an ordered group and P is a real closed field defined on a bounded interval (joint work with Peterzil)\,(b) tame expansions (M\, P) of a real closed field M by a predicate P\, such as expansions with o-minimal open core (work in progress with Gunaydin and Hieronymi).The analysis of definable groups first goes through a local level\, where a pertinent notion of a pregeometry and generic elements is each time introduced.
URL:https://www.math.ens.psl.eu/evenement/pregeometries-and-definable-groups/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131115T160000
DTEND;TZID=Europe/Paris:20131115T160000
DTSTAMP:20261028T033620
CREATED:20131115T150000Z
LAST-MODIFIED:20211104T094302Z
UID:8150-1384531200-1384531200@www.math.ens.psl.eu
SUMMARY:Autour de l'algébrisation des fibrés en droites
DESCRIPTION:
URL:https://www.math.ens.psl.eu/evenement/autour-de-lalgebrisation-des-fibres-en-droites/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131115T141500
DTEND;TZID=Europe/Paris:20131115T141500
DTSTAMP:20261028T033620
CREATED:20131115T131500Z
LAST-MODIFIED:20211104T094301Z
UID:8149-1384524900-1384524900@www.math.ens.psl.eu
SUMMARY:Du théorème du noyau de Manin aux équations de Pell-Fermat.
DESCRIPTION:
URL:https://www.math.ens.psl.eu/evenement/du-theoreme-du-noyau-de-manin-aux-equations-de-pell-fermat/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131115T110000
DTEND;TZID=Europe/Paris:20131115T110000
DTSTAMP:20261028T033620
CREATED:20131115T100000Z
LAST-MODIFIED:20211104T094301Z
UID:8148-1384513200-1384513200@www.math.ens.psl.eu
SUMMARY:Valued differential fields
DESCRIPTION:We consider valued fields of equicharacteristic zero equipped with a continuous derivation. This class of structures is rather diverse\, including both monotone differential fields and asymptotic differential fields. (These terms will be defined.) Nevertheless\, some results can be established uniformly for the entire class: algebraic extensions\, construction of residue field extensions\, the Equalizer Theorem\, construction of immediate extensions\, differential-henselianity. Next I will revisit Scanlon’s thesis on the model theory of differential-henselian monotone differential fields with enough constants. Time permitting I will add some remarks on the case of asymptotic differential fields.The above is (a small part of) ongoing joint work with Matthias Aschenbrenner and Joris van der Hoeven focused on developing a model theory for differential fields of transseries.
URL:https://www.math.ens.psl.eu/evenement/valued-differential-fields/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131004T160000
DTEND;TZID=Europe/Paris:20131004T160000
DTSTAMP:20261028T033620
CREATED:20131004T140000Z
LAST-MODIFIED:20211104T094057Z
UID:8132-1380902400-1380902400@www.math.ens.psl.eu
SUMMARY:Tame definable topological dynamics
DESCRIPTION:(Joint work with Pierre Simon) I will present some new results on definably amenable groups in NIP theories (typical examples of which are definably amenable groups in o-minimal theories\, algebraically closed valued fields and p-adics). In particular I will demonstrate that in this context various notions of genericity coincide (answering some questions of Newelski and Petrykowski) and a characterization of ergodic measures will be given. Arguments rely on the theory of forking for types and measures in NIP theories and the so-called (p\,q)-theorem from combinatorics.If time permits\, I will describe how these results generalize to homogeneous spaces\, ind-definable groups and action of the group of automorphisms\, and how these developments can be viewed as a study of the definable case of abstract tame dynamical systems introduced by Glasner.
URL:https://www.math.ens.psl.eu/evenement/tame-definable-topological-dynamics/
LOCATION:ENS salle W (escalier B 4è étage)
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131004T110000
DTEND;TZID=Europe/Paris:20131004T110000
DTSTAMP:20261028T033620
CREATED:20131004T090000Z
LAST-MODIFIED:20211104T094058Z
UID:8134-1380884400-1380884400@www.math.ens.psl.eu
SUMMARY:Church-Turing computability of the étale cohomology mod l
DESCRIPTION:[Work in common with Fabrice Orgogozo]The dimension of the étale cohomology groups\, with coefficients in Z/lZ\, of a scheme of finite type over an algebraically closed field of characteristic different from l\, is computable in the sense of Church-Turing. To prove this\, we construct a hypercovering of X by schemes (analogous to Artin’s ?Roegood neighborhoods?R) having algorithmically testable geometric properties which allow to reduce the computation of the cohomology of X to that of their completed fundamental group.
URL:https://www.math.ens.psl.eu/evenement/church-turing-computability-of-the-etale-cohomology-mod-l/
LOCATION:ENS salle W (escalier B 4è étage)
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20131004T000000
DTEND;TZID=Europe/Paris:20131004T000000
DTSTAMP:20261028T033620
CREATED:20131003T220000Z
LAST-MODIFIED:20211104T094057Z
UID:8133-1380844800-1380844800@www.math.ens.psl.eu
SUMMARY:Strictly convergent rigid subanalytic sets
DESCRIPTION:Let K be a non-archimedean complete normed field\, K_alg the algebraic closure of K and let L be the language of normed fields augmented with symbols for the strictly convergent powerseries over K. Strictly convergent rigid subanalytic sets over K are the subsets of (K_alg)^n definable in L. I will survey what is known about these sets\, including recent joint results with Raf Cluckers.
URL:https://www.math.ens.psl.eu/evenement/strictly-convergent-rigid-subanalytic-sets/
LOCATION:ENS salle W (escalier B 4è étage)
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130621T160000
DTEND;TZID=Europe/Paris:20130621T160000
DTSTAMP:20261028T033620
CREATED:20130621T140000Z
LAST-MODIFIED:20211104T093841Z
UID:8125-1371830400-1371830400@www.math.ens.psl.eu
SUMMARY:Newton-Puiseux Theorem for convergent generalised power series
DESCRIPTION:A generalised power series (in several variables) is a series with real nonnegative exponents whose support is contained in a cartesian product of well-ordered subsets of the real line. Let A be the collection of all convergent generalised power series. I will show that\, if f(x_1\,…\,x_n\,y) is in A\, then the solutions y=g(x_1\,…\,x_n) of the equation f=0 can be expressed as terms of the language which has a symbol for every function in A and a symbol for division. The construction of the terms is rather explicit. If instead of solving just one equation one wants to solve a system of equations\, then one needs a different argument and the proof I will exhibit is a lot less constructive.
URL:https://www.math.ens.psl.eu/evenement/newton-puiseux-theorem-for-convergent-generalised-power-series/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130621T141500
DTEND;TZID=Europe/Paris:20130621T141500
DTSTAMP:20261028T033620
CREATED:20130621T121500Z
LAST-MODIFIED:20211104T093840Z
UID:8124-1371824100-1371824100@www.math.ens.psl.eu
SUMMARY:NIP\, amenability\, and dynamics
DESCRIPTION:I will discuss problems around definably amenable groups in NIP theories\, informed by some invariants coming from topological dynamics.
URL:https://www.math.ens.psl.eu/evenement/nip-amenability-and-dynamics/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130621T110000
DTEND;TZID=Europe/Paris:20130621T110000
DTSTAMP:20261028T033620
CREATED:20130621T090000Z
LAST-MODIFIED:20211104T093840Z
UID:8123-1371812400-1371812400@www.math.ens.psl.eu
SUMMARY:Positivity of line bundles on varieties defined over non-Archimedean fields
DESCRIPTION:For algebraic varieties defined over the complex numbers\, one can study geometry using both algebraic and analytic methods. Over a non-Archimedean field\, one can try to do the same thing using Berkovich spaces. I will discuss positivity notions for metrics on line bundles on varieties defined over discretely or trivially valued fields.
URL:https://www.math.ens.psl.eu/evenement/positivity-of-line-bundles-on-varieties-defined-over-non-archimedean-fields/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130419T160000
DTEND;TZID=Europe/Paris:20130419T160000
DTSTAMP:20261028T033620
CREATED:20130419T140000Z
LAST-MODIFIED:20211104T093820Z
UID:8116-1366387200-1366387200@www.math.ens.psl.eu
SUMMARY:Imaginaries in valued fields
DESCRIPTION:It is now well-known what sorts have to be added to a valued field in order to achieve elimination of imaginaries. It is also known that these sorts do not suffice to eliminate imaginaries when the field is enhanced by restricted analytic functions\, despite the fact that the theories still have quantifier elimination. In this talk\, I will attempt to convey the intuition about the definable sets in a valued field that underlies all of these results (while explaining the model-theoretic terminology in the above).
URL:https://www.math.ens.psl.eu/evenement/imaginaries-in-valued-fields/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130419T141500
DTEND;TZID=Europe/Paris:20130419T141500
DTSTAMP:20261028T033620
CREATED:20130419T121500Z
LAST-MODIFIED:20211104T093241Z
UID:8115-1366380900-1366380900@www.math.ens.psl.eu
SUMMARY:Sheaves on subanalytic sites
DESCRIPTION:Sheaf theory is not well suited to study objects which are not defined by local properties. It is the case\, for example\, of functional spaces with growth conditions\, as tempered distributions. Since the study of the solutions of a system of PDE in these spaces is of great importance (solutions of irregular D-modules\, Laplace transform\, etc.)\, many ways have been explored by the specialists to overcome this problem. For this purpose Kashiwara and Schapira introduced the subanalytic site and proved that some of these spaces can be realized as sheaves on a subanalytic site. In this talk we will recall the theory of subanalytic sheaves and give an overview of some recent developments and applications.
URL:https://www.math.ens.psl.eu/evenement/sheaves-on-subanalytic-sites/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20130419T110000
DTEND;TZID=Europe/Paris:20130419T110000
DTSTAMP:20261028T033620
CREATED:20130419T090000Z
LAST-MODIFIED:20211104T093241Z
UID:8114-1366369200-1366369200@www.math.ens.psl.eu
SUMMARY:Ensembles sous-analytiques surconvergents dans les espaces de Berkovich
DESCRIPTION:Si X est un espace k-affinoïde (k étant un corps non-archimédien)\, un sous-ensemble S de X est dit sous-analytique surconvergent si on peut ?Roeessentiellement?R l’écrire S=f(Y) où f est un morphisme surconvergent d’espaces affinoïdes.Nous expliquerons d’abord comment décrire ces ensembles en n’utilisant que des fonctions de X\, i.e. sans avoir recours à une projection. Il s’agit d’une version géométrique d’un résultat de H. Schoutens qui utilise l’élimination des quantificateurs dans ACVF.Nous montrerons ensuite que les ensembles sous-analytiques surconvergents peuvent être définis localement pour la topologie de Berkovich\, mais pas pour la G-topologie.
URL:https://www.math.ens.psl.eu/evenement/ensembles-sous-analytiques-surconvergents-dans-les-espaces-de-berkovich/
LOCATION:IHP Salle 314
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20120406T160000
DTEND;TZID=Europe/Paris:20120406T173000
DTSTAMP:20261028T033620
CREATED:20120406T140000Z
LAST-MODIFIED:20211104T092155Z
UID:8082-1333728000-1333733400@www.math.ens.psl.eu
SUMMARY:Motivic Lipschitz continuity
DESCRIPTION:In a general set-up for non-archimedean geometry\, we show how local Lipschitz continuity implies piecewise Lipschitz continuity (globally on the whole piece) for definable functions. This is joint work with G. Comte and F. Loeser which generalizes previous work by the same three authors for a fixed p-adic field in [GAFA\, 2010] and which fits in a broader program at the interplay of arithmetic and non-archimedean geometry.
URL:https://www.math.ens.psl.eu/evenement/motivic-lipschitz-continuity/
LOCATION:Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20120406T160000
DTEND;TZID=Europe/Paris:20120406T160000
DTSTAMP:20261028T033620
CREATED:20120406T140000Z
LAST-MODIFIED:20211104T092141Z
UID:8080-1333728000-1333728000@www.math.ens.psl.eu
SUMMARY:Generalizations of stability and NTP2
DESCRIPTION:
URL:https://www.math.ens.psl.eu/evenement/generalizations-of-stability-and-ntp2/
LOCATION:Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20120406T140000
DTEND;TZID=Europe/Paris:20120406T153000
DTSTAMP:20261028T033620
CREATED:20120406T120000Z
LAST-MODIFIED:20211104T092155Z
UID:8081-1333720800-1333726200@www.math.ens.psl.eu
SUMMARY:Fibres de Milnor motiviques en géométrie semi-algébrique réelle
DESCRIPTION:J’expliquerai un travail en commun avec Goulwen Fichou\, qui consiste à mettre en place un anneau de Grothendieck K_0(BSA_R) des formules semi-algébriques grâce auquel on peut définir\, sur le modèle complexe\, des fonctions zêta motiviques de singularités réelles. On montre que ces fonctions zêtas sont rationnelles et que leur expression rationnelle définit des fibres de Milnor motiviques des singularités réelles. Il s’agit d’éléments de l’anneau K_0(BSA_R)otimes Z[1/2] dont on montre qu’ils se réalisent\, via le morphisme caractéristique d’Euler\, sur la caractéristique d’Euler des fibres de Milnor ensemblistes correspondantes.
URL:https://www.math.ens.psl.eu/evenement/fibres-de-milnor-motiviques-en-geometrie-semi-algebrique-reelle/
LOCATION:Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111104T160000
DTEND;TZID=Europe/Paris:20111104T173000
DTSTAMP:20261028T033620
CREATED:20111104T150000Z
LAST-MODIFIED:20211104T091530Z
UID:8045-1320422400-1320427800@www.math.ens.psl.eu
SUMMARY:Algebre differentielle et geometrie des orbites. Une nouvelle correpondance galoisienne.
DESCRIPTION:La théorie classique de Picard-Vessiot fournit une correspondance galoisienne pour les extensions de corps différentiels. Nous présenterons une correspondance plus fine\, sous forme d’une anti-équivalence de catégories entre algèbres de solutions associées à une équation différentielle linéaire (algèbres différentielles engendrées par un nombre fini de polynômes en les solutions fondamentales de l’équation) et variétés affines quasi-homogènes sous l’action du groupe de Galois différentiel. Une telle correspondance joue aussi dans le contexte plus général des connexions (intégrables ou non). Nous évoquerons le parti que cette correspondance permet de tirer\, en algèbre différentielle\, de la riche théorie des variétés quasi-homogènes.
URL:https://www.math.ens.psl.eu/evenement/algebre-differentielle-et-geometrie-des-orbites-une-nouvelle-correpondance-galoisienne/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111104T140000
DTEND;TZID=Europe/Paris:20111104T153000
DTSTAMP:20261028T033620
CREATED:20111104T130000Z
LAST-MODIFIED:20211104T091529Z
UID:8044-1320415200-1320420600@www.math.ens.psl.eu
SUMMARY:Inverse problems in the Parameterized Picard-Vessiot Theory
DESCRIPTION:The parameterized Picard-Vessiot theory aims at studying the differential behavior of solutions of parameterized linear differential equations. It associates to such an equation a linear differential algebraic group (LDAG)\, that is\, a group of matrices whose entries are functions satisfying a fixed set of differential equations. After giving an introduction to this theory\, I will show that not all LDAGs can occur as Galois groups over k(x)\, the field of rational functions in x whose coefficients are functions of a parameter t and characterize those LDAGs that do occur.
URL:https://www.math.ens.psl.eu/evenement/inverse-problems-in-the-parameterized-picard-vessiot-theory/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111104T110000
DTEND;TZID=Europe/Paris:20111104T123000
DTSTAMP:20261028T033620
CREATED:20111104T100000Z
LAST-MODIFIED:20211104T091529Z
UID:8043-1320404400-1320409800@www.math.ens.psl.eu
SUMMARY:Theoreme de Szemeredi et structures pseudofinies
DESCRIPTION:
URL:https://www.math.ens.psl.eu/evenement/theoreme-de-szemeredi-et-structures-pseudofinies/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111007T160000
DTEND;TZID=Europe/Paris:20111007T173000
DTSTAMP:20261028T033620
CREATED:20111007T140000Z
LAST-MODIFIED:20211104T091201Z
UID:8026-1318003200-1318008600@www.math.ens.psl.eu
SUMMARY:Les nombres surréels comme corps de transséries - séries exp-log.
DESCRIPTION:
URL:https://www.math.ens.psl.eu/evenement/les-nombres-surreels-comme-corps-de-transseries-series-exp-log/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111007T140000
DTEND;TZID=Europe/Paris:20111007T153000
DTSTAMP:20261028T033620
CREATED:20111007T120000Z
LAST-MODIFIED:20211104T091002Z
UID:8025-1317996000-1318001400@www.math.ens.psl.eu
SUMMARY:Introduction a l'homologie tropicale
DESCRIPTION:Dans cet exposé\, on présentera plusieurs notions fondamentales de la géométrie tropicale et on s’intéressera tout particulièrement aux groupes d’homologie dans le cadre tropical. Sous certaines conditions\, une variété tropicale peut être approximée par une famille à un paramètre de variétés complexes\, et des caractéristiques importantes des variétés de cette famille peuvent être exprimées en termes des groupes d’homologie tropicaux de la variété tropicale considérée (travail en commun avec L. Katzarkov\, G. Mikhalkin et I. Zharkov).
URL:https://www.math.ens.psl.eu/evenement/introduction-a-lhomologie-tropicale/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20111007T110000
DTEND;TZID=Europe/Paris:20111007T123000
DTSTAMP:20261028T033620
CREATED:20111007T090000Z
LAST-MODIFIED:20211104T091002Z
UID:8024-1317985200-1317990600@www.math.ens.psl.eu
SUMMARY:Restrained structures
DESCRIPTION:We study first-order expansions of the real field that are restrained\, i.e. that do not define the set of natural numbers. Being restrained is equivalent to several other notions of tameness.In particular: in a restrained structure\, all reasonable notions of dimension (topological\, Hausdorff\, Minkowski\, …) coincide for unary closed definable sets (we also have partial results for non-unary sets)
URL:https://www.math.ens.psl.eu/evenement/restrained-structures/
LOCATION:amphithéâtre Rataud
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110506T160000
DTEND;TZID=Europe/Paris:20110506T173000
DTSTAMP:20261028T033620
CREATED:20110506T140000Z
LAST-MODIFIED:20211104T090601Z
UID:8014-1304697600-1304703000@www.math.ens.psl.eu
SUMMARY:Soficité des groupes de Cremona
DESCRIPTION:Le groupe de Cremona Crn(C) est le groupe des transformations birationnelles de Cn. Au contraire des groupes de matrices\, on ne sait pas\, si n?oo2\, s’il possède des sous-groupes de type fini non résiduellement finis. Je montrerai une version faible dans cette direction: il est sofique\, c’est-à-dire approximable\, en un sens convenable\, par des groupes finis (notion introduite par M. Gromov et B. Weiss). J’introduirai en détail toutes les notions utilisées.
URL:https://www.math.ens.psl.eu/evenement/soficite-des-groupes-de-cremona/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110506T140000
DTEND;TZID=Europe/Paris:20110506T153000
DTSTAMP:20261028T033620
CREATED:20110506T120000Z
LAST-MODIFIED:20211104T090601Z
UID:8013-1304690400-1304695800@www.math.ens.psl.eu
SUMMARY:Topology of definable groups in tame structures
DESCRIPTION:I will survey some results on definable groups in o-minimal structures\, some old\, some new\, emphasizing the interplay between algebra\, logic\, and topology. In particular I will show how a combination of techniques from model theory and algebraic topology lead to the determination of the definable homeomorphism type of definable abelian groups in dimension not equal to 4 (joint work with E. Baro). If time permits\, I will consider the problem of finding a tame definable context\, larger than o-minimality\, which is suitable for the study of universal covers (work in progress with M. Mamino).
URL:https://www.math.ens.psl.eu/evenement/topology-of-definable-groups-in-tame-structures/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110506T110000
DTEND;TZID=Europe/Paris:20110506T123000
DTSTAMP:20261028T033620
CREATED:20110506T090000Z
LAST-MODIFIED:20211104T090601Z
UID:8012-1304679600-1304685000@www.math.ens.psl.eu
SUMMARY:Hilbert's fifth problem and applications
DESCRIPTION:Hilbert’s fifth problem asks whether every locally euclidean group G can be equipped with a real analytic structure (compatible with the topology) so that the group operations become real analytic
URL:https://www.math.ens.psl.eu/evenement/hilberts-fifth-problem-and-applications/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110408T160000
DTEND;TZID=Europe/Paris:20110408T173000
DTSTAMP:20261028T033620
CREATED:20110408T140000Z
LAST-MODIFIED:20211104T090600Z
UID:8011-1302278400-1302283800@www.math.ens.psl.eu
SUMMARY:Chai's conjecture and Fubini properties of motivic integrals.
DESCRIPTION:Let K be a discretely valued field with perfect residue field k. Let G be a semi-abelian variety over K\, i.e.\, an extension of an abelian K-variety A by a K-torus T. The Néron lft-model of G is the minimal extension of G to a smooth group scheme over the value ring of K. We say that G has semi-abelian reduction if the identity component of the special fiber of the Néron lft-model of G is a semi-abelian k-variety. By Grothendieck’s Semi-Stable Reduction Theorem\, G acquires semi-abelian reduction over some finite separable extension K’ of K. Chai’s base change conductor c(G) is a positive rational number that measures the defect of semi-abelian reduction of G over K. Chai conjectured that c(G)=c(A)+c(T)\, and he proved this property if k is finite and also if K has characteristic zero. The proof of the finite residue field case uses Fubini’s theorem for integrals with respect to the Haar measure on the completion of K. The proof of the case where K has characteristic zero uses completely different methods. In this talk\, we will first give a general introduction to Néron lft-models and the base change conductor. Then we’ll show how one can use Loeser and Sebag’s motivic integration on rigid varieties to reformulate Chai’s conjecture as a Fubini property for motivic integrals\, and how one can use Cluckers and Loeser’s motivic integration on definable sets to prove this Fubini property if K has characteristic zero. This is joint work with Raf Cluckers and François Loeser.
URL:https://www.math.ens.psl.eu/evenement/chais-conjecture-and-fubini-properties-of-motivic-integrals/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110408T140000
DTEND;TZID=Europe/Paris:20110408T153000
DTSTAMP:20261028T033620
CREATED:20110408T120000Z
LAST-MODIFIED:20211104T090547Z
UID:8010-1302271200-1302276600@www.math.ens.psl.eu
SUMMARY:Théorie des modèles des corps munis d'une dérivation de Hasse
DESCRIPTION:Je commencerai par présenter les résultats basiques de la théorie des modèles des corps ?Roedifférentiellement clos?Roe au sens des dérivations de Hasse en toute caractéristique.Ensuite j’introduirai les notions de D-prolongations et de D-structures sur une variété\, pour D une dérivation de Hasse\, et expliquerai les liens avec des théorèmes de descente sur le corps des constantes. Ce contexte nous permettra de ?Roerevisiter?R avec un point de vue différent certaines des notions que j’avais introduites lors de mon exposé du 19 novembre à ce même séminaire ou qui avaient été évoquées dans l’exposé du 17 décembre de Anand Pillay. Il ne sera pas nécessaire d’avoir suivi l’un ou l’autre de ces exposés précédents pour suivre celui-ci.
URL:https://www.math.ens.psl.eu/evenement/theorie-des-modeles-des-corps-munis-dune-derivation-de-hasse/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20110408T110000
DTEND;TZID=Europe/Paris:20110408T123000
DTSTAMP:20261028T033620
CREATED:20110408T090000Z
LAST-MODIFIED:20211104T090546Z
UID:8009-1302260400-1302265800@www.math.ens.psl.eu
SUMMARY:Sur le type d'homotopie des espaces de Berkovich.
DESCRIPTION:J’expliquerai comment on peut aborder les résultats récents de E. Hrushovski et F. Loeser sur la topologie des variétés algébriques sur un corps non archimédien en reprenant le point de vue de Berkovich\, fondé sur des théorèmes de désingularisation.
URL:https://www.math.ens.psl.eu/evenement/sur-le-type-dhomotopie-des-espaces-de-berkovich/
LOCATION:ENS Salle W
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
END:VCALENDAR