Séminaire Groupes, Représentations et Géométrie

salle 1016, 1er étage, Bâtiment Sophie Germain, 8 place Aurélie Nemours, 75013 Paris

Organisateurs : , , , , , , et .

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Vendredi 11 mai 2018 à 10h30

Changjian SU (IHES), On a conjecture of Bump–Nakasuji–Naruse about the Casselman basis.
[Let G be a split p-adic reductive group. In the Iwahori invariants of a unramified principal series representation of G, there are two bases. One of them is the Casselman basis, which played an important role in the Casselman–Shalika formula. In this talk, I will prove a conjecture of Bump, Nakasuji and Naruse about the transition matrix between these two bases. The idea is to transform the problem into the Langlands dual side, and use motivic Chern classes defined by Brasselet–Schurmann–Yokura and the K-theoretic stable envelope of Maulik–Okounkov. This is based on joint work with Aluffi, Mihalcea and Schurmann.]

Vendredi 18 mai 2018 à 10h30

Anthony JOSEPH (Weizmann Institute), Canonical S-graphs, trails and relations in Demazure modules.
[After Berenstein and Zevelinsky, the structure of the Kashiwara B(∞) crystal is determined by trails in the fundamental modules corresponding to the reduced decomposition chosen. However trails are not combinatorially defined. Up to the conjectural absence of ``false” trails it is shown that trails are given combinatorially through the integer points of convex sets determined by the canonical S-graphs. The proof involves identities in Demazure modules arising from the Chevalley-Serre relations.]

Vendredi 25 mai 2018 à 10h30

Boris PIOLINE (UPMC-Sorbonne Universités), A physicist viewpoint on the cohomology of quiver moduli.
[Moduli spaces of quiver representations naturally appear in physics in the context of the dynamics of supersymmetric black holes. Based on physics intuition, I will propose concrete formulae for computing the Poincaré polynomial of quiver moduli spaces in terms of new invariants which do not depend on the stability parameters. Based on joint work with S. Alexandrov, J. Manschot, Ashoke Sen [arXiv: 1207.2230, 1404.7154,1804.06928]]

Vendredi 1er juin 2018 à 10h30

Quoc P. HO (IST Vienne)

Vendredi 8 juin 2018 à 10h30

Salim ROSTAM (Université de Versailles)

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Groupes, représentations et géométrie.
Dernière modification : le 22/05/2018