"Calcul
différentiel simplicial"
14 octobre 2010 : Charles BOUBEL
(Université de Strasbourg) :
"L'algèbre des endomorphismes parallèles d'un germe de
métrique pseudo-riemannienne".
20 - 22 octobre 2010 :
Journées MNRS
(à Reims)
18 novembre 2010 : Wolfgang BERTRAM
(Institut Elie Cartan) :
"Homotopes d'espaces symétriques et variété de
structure"
25 novembre 2010 : Wolfgang BERTRAM
(Institut Elie Cartan) :
"Homotopes d'espaces symétriques et variété de
structure (suite)"
2 décembre 2010 : Inka
KLOSTERMANN (Université de Cologne) :
"Formulas for Hall-Littlewood polynomials"
7 décembre 2010 (mardi)
à 14 heures 30 : Stéphane GAUSSENT :
soutenance d'habilitation à diriger des recherches.
9 et 10 décembre 2010 : groupe de travail sur la grassmannienne affine double :
- Jeudi 9, 14h.
Stéphane Gaussent, Grassmannienne affine : définition et
exemples.
- Jeudi 9, 16h.
Dragos Fratila, Isomorphisme de Satake et formules de
Gindikin-Karpelevich.
- Vendredi 10, 10h. Pierre Baumann, Satake géométrique,
d’après Lusztig, Ginzburg,
Beilinson-Drinfeld,
Mirkovic-Vilonen,
...
- Vendredi 10, 14h. Manish Patnaik, The Satake map for p-adic loop
groups and the
analogue
of
Macdonald’s
formula
for
spherical
functions.
- Vendredi 10, 16h.
Olivier Schiffmann, Algèbres de Hecke affine double
(d’après un article de Kapranov).
16 décembre 2010 : Marc
CABANES (Université
Paris
7)
"Rétraction d'Okuyama dans le complexe de Coxeter, et
applications"
8 juin 2011 (16 h 30, salle de conf.): Greg Kuperberg (UC Davis et UJF Grenoble) :
"What is quantum probability?"
Abstract: Quantum mechanics is difficult for many people to understand
because it is difficult to believe. The heart of the problem is quantum
probability, which is an entirely rigorous theory; nonetheless even many
working mathematicians have trouble believing it. (Quantum field theory is
far from entirely rigorous, but that is a very different issue that I will
not discuss.) In the past 15 years or so, quantum probability has greatly
expanded as a mathematical topic in the guise of quantum computation and
quantum information theory. In this talk, I will discuss some of the ideas
of quantum probability, quantum computation, and quantum information,
using the language of pure mathematics. A particular theme is that a good
scientific interpretation of quantum probability can be exactly matched
to basic ideas in operator algebras.
9 juin 2011 : Greg Kuperberg (UC Davis et UJF Grenoble) :
"Buildings, spiders, and geometric Satake"
Abstract: Louis Kauffman found a special description of the Jones polynomial
and the representation theory of $U_q(\mathfrak{sl}(2))$ in which each
skein space has a basis of planar matchings. There is a similar calculus
(discovered independently by myself and the late François Jaeger) for
each of the three rank 2 simple Lie algebras $A_2$, $B_2$, and $G_2$.
These skein theories, called ``spiders", can also be viewed as Gr\"obner-type
presentations of pivotal categories. In each of the four cases (optionally
also including the semisimple case $A_1 \times A_1$), the Gr\"obner basis
property yields a basis of skein diagrams called ``webs". The basis webs
are defined by an interesting non-positive curvature condition.
I will discuss a new connection between these spiders and the geometric
Satake correspondence, which relates the representation category of a
simple Lie algebra to an affine building of the Langlands dual algebra.
In particular, any such building is $\CAT(0)$, which seems to explain the
non-positive curvature of basis webs.
Exposés
antérieurs
au séminaire d'analyse harmonique:
2000/01
2002/03
2003/04
2004/05
2005/06
2006/07
2007/08
2008/09
2009/2010
Groupes de travail sur les aspects algébriques des groupes de Lie Coordination : G. Rousseau
Seminaire Analyse, Géométrie et Algèbre (LMAM Metz)