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X-WR-CALNAME:Département de mathématiques et applications
X-ORIGINAL-URL:https://www.math.ens.psl.eu
X-WR-CALDESC:évènements pour Département de mathématiques et applications
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BEGIN:VTIMEZONE
TZID:Europe/Paris
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20220327T010000
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BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20221030T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220202T110000
DTEND;TZID=Europe/Paris:20220202T120000
DTSTAMP:20260406T054714
CREATED:20220214T103412Z
LAST-MODIFIED:20220214T103412Z
UID:15206-1643799600-1643803200@www.math.ens.psl.eu
SUMMARY:Julien Marché\, raconte-moi la topologie quantique et le nombre d'or !
DESCRIPTION:Si la topologie quantique est née des travaux de Jones\, Kauffman et Witten à la fin des années 1980\, on peut lui trouver des racines plus anciennes. En partant des polynômes chromatiques des graphes (Birkhoff 1912)\, revisités par Tutte dans les années 1960\, on va expliquer comment en tirer des représentations des groupes modulaires des surfaces toujours liées au nombre d’or. Parmi elles\, le groupe de l’icosaèdre et l’uniformisation de surfaces trouvées par Hirzebruch.
URL:https://www.math.ens.psl.eu/evenement/julien-marche-raconte-moi-la-topologie-quantique-et-le-nombre-dor/
LOCATION:En salle W au DMA\, ou sur Zoom
CATEGORIES:Séminaire Raconte-moi
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220208T150000
DTEND;TZID=Europe/Paris:20220208T180000
DTSTAMP:20260406T054714
CREATED:20220129T155631Z
LAST-MODIFIED:20220129T160053Z
UID:15136-1644332400-1644343200@www.math.ens.psl.eu
SUMMARY:Un après-midi de sous-groupes aleatoires invariants ou stationaires
DESCRIPTION:ZOOM: https://us02web.zoom.us/j/81548053762\nID: 815 4805 3762\nMot de passe:\nG est un Graphe de Cayley du groupe libre à 107 générateurs. Quel est\nle degré de ce graphe? Tapez le numéro à trois chiffres comme un mot\nde passe. \n15.00 – 15.45    Tsachik Gelander (Weizmann Institute)\, « Stationary\nrandom discrete subgroups of semisimple Lie groups » \n16.00 – 16.45     Matthieu Joseph (ENS Lyon)\, « Allosteric actions of\nsurface groups » \n17.15 – 18.00     Yair Hartman (Ben Gurion University)\,\n« Intersectional Invariant Random Subgroups » \nVous pourrez trouver les résumés sur le site du séminaire: \nhttps://sites.google.com/site/annaerschler/grseminar
URL:https://www.math.ens.psl.eu/evenement/un-apres-midi-de-sous-groupes-aleatoires-invariants-ou-stationaires/
LOCATION:Zoom
CATEGORIES:Séminaire de théorie des groupes à l’ENS
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220215T160000
DTEND;TZID=Europe/Paris:20220215T173000
DTSTAMP:20260406T054714
CREATED:20220207T145840Z
LAST-MODIFIED:20220211T161554Z
UID:15168-1644940800-1644946200@www.math.ens.psl.eu
SUMMARY:Groups definable in partial differential fields with an automorphism
DESCRIPTION:This is a joint work with Ronald Bustamante Medina and Zoé Chatzidakis.\nIn this talk we are interested in differential and difference fields from the model-theoretic point of view. A differential field is a field with a set of commuting derivations and a difference-differential field is a differential field equipped with an automorphism which commutes with the derivations.\nCassidy studied definable groups in differentially closed fields\, in particular she studied Zariski dense definable subgroups of simple algebraic groups and showed that they are isomorphic to the rational points of an algebraic group over some definable field. In this talk we study groups definable in existentially closed difference-differential fields. In particular\, we study Zariski dense definable subgroups of simple algebraic groups\, and show an\nanalogue of Phyllis Cassidy’s result for partial differential fields.
URL:https://www.math.ens.psl.eu/evenement/groups-definable-in-partial-differential-fields-with-an-automorphism/
LOCATION:Sophie Germain salle 1016.
CATEGORIES:Théorie des Modèles et Groupes
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220216T110000
DTEND;TZID=Europe/Paris:20220216T120000
DTSTAMP:20260406T054714
CREATED:20220214T103226Z
LAST-MODIFIED:20220214T103301Z
UID:15204-1645009200-1645012800@www.math.ens.psl.eu
SUMMARY:Léonard Pille-Schneider\, raconte-moi les espaces hybrides !
DESCRIPTION:Soit X=(X_t) une famille de variétés algébriques complexes paramétrée par le disque épointé\, dont les équations ont une singularité méromorphe en t=0. Le but de cet exposé est d’expliquer comment associer à cette famille un espace dit hybride\, permettant de voir les variétés complexes X_t dégénérer vers l’espace analytique non-archimédien obtenu en interprétant X comme une variété algébrique sur le corps des séries de Laurent. Je donnerai aussi des applications géométriques de cette construction.
URL:https://www.math.ens.psl.eu/evenement/leonard-pille-schneider-raconte-moi-les-espaces-hybrides/
LOCATION:En salle W au DMA\, ou sur Zoom
CATEGORIES:Séminaire Raconte-moi
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220218T140000
DTEND;TZID=Europe/Paris:20220218T153000
DTSTAMP:20260406T054714
CREATED:20220204T103217Z
LAST-MODIFIED:20220204T103815Z
UID:15163-1645192800-1645198200@www.math.ens.psl.eu
SUMMARY:The Kemperman inverse 	problem
DESCRIPTION:Let G be a connected locally compact group with a left Haar measure μ\, and let A\,B ⊆ G be nonempty and compact. Assume further that G is unimodular\, i.e.\, μ is also the right Haar measure; this holds\, e.g.\, when G is compact\, a nilpotent Lie group\, or a semisimple Lie group. In 1964\, Kemperman showed that \nμ(AB) ≥ min {μ(A)+μ(B)\, μ(G)} .\nThe Kemperman inverse problem (proposed by Griesmer\, Kemperman\, and Tao) asks when the equality happens or nearly happens. I will discuss the recent solution of this problem\, highlighting the connections to model theory. (Joint with Jinpeng An\, Yifan Jing\, and Ruixiang Zhang).
URL:https://www.math.ens.psl.eu/evenement/the-kemperman-inverse-problem/
LOCATION:Zoom
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220218T154500
DTEND;TZID=Europe/Paris:20220218T171500
DTSTAMP:20260406T054714
CREATED:20220203T145355Z
LAST-MODIFIED:20220211T161457Z
UID:15158-1645199100-1645204500@www.math.ens.psl.eu
SUMMARY:Not Pfaffian
DESCRIPTION:This talk describes the connection between /strong minimality/ of the differential equation satisfied by an complex analytic function and the real and imaginary parts of the function being /Pfaffian/. The talk will not assume the audience knows these notions previously\, and will attempt to motivate why each of them are important notions in various areas. The connection we give\, combined with a theorem of Freitag and Scanlon (2017) provides the answer to a question of Binyamini and Novikov (2017). We also answer a question of Bianconi (2016). We give what seem to be the first examples of functions which are definable in o-minimal expansions of the reals and are differentially algebraic\, but not Pfaffian.
URL:https://www.math.ens.psl.eu/evenement/not-pfaffian/
LOCATION:Zoom
CATEGORIES:Séminaire Géométrie et théorie des modèles
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20220222T160000
DTEND;TZID=Europe/Paris:20220222T173000
DTSTAMP:20260406T054714
CREATED:20220214T184113Z
LAST-MODIFIED:20220214T184113Z
UID:15214-1645545600-1645551000@www.math.ens.psl.eu
SUMMARY:NIPn fields part 2: random hypergraphs and NIPn CHIPS transfer
DESCRIPTION:A core question in the model theory of fields is to understand how combinatorial patterns and algebraic properties interact. The study of NIPn fields\, which can’t express the edge relation of random n-hypergraph\, is linked to henselianity. In this talk\, we use Chernikov and Hils conditions to obtain transfer in some situations\, that is\, under some algebraic assumptions\, it is enough to know that the residue field of a henselian valued field is NIPn in order to known that it is itself NIPn\, and we discuss consequences on hypothetical strictly NIPn fields.
URL:https://www.math.ens.psl.eu/evenement/nipn-fields-part-2-random-hypergraphs-and-nipn-chips-transfer/
LOCATION:salle 1016 Sophie Germain
CATEGORIES:Théorie des Modèles et Groupes
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