Filtrations of the modules for Chevalley groups arising from admissible lattices.
On décrit les foncteurs polynomiaux, des groupes abéliens libres vers les groupes abéliens, comme des diagrammes de groupes abéliens dont on explicite les relations.
Soit un groupe, soit une représentation complètement réductible de , et soit un système de générateurs de l’algèbre des fonctions polynômes sur , invariantes par . Dans l’article on démontre que toute fonction analytique sur , invariante par , peut s’écrire comme fonction analytique en ; on obtient également un résultat analogue pour les fonctions indéfiniment différentiables.
We describe a correspondence between -invariant tensors and graphs. We then show how this correspondence accommodates various types of symmetries and orientations.
Following Lusztig, we consider a Coxeter group together with a weight function. Geck showed that the Kazhdan-Lusztig cells of are compatible with parabolic subgroups. In this paper, we generalize this argument to some subsets of which may not be parabolic subgroups. We obtain two applications: we show that under specific technical conditions on the parameters, the cells of certain parabolic subgroups of are cells in the whole group, and we decompose the affine Weyl group of type into left...
We generalize the definition of quiver representation to arbitrary reductive groups. The classical definition corresponds to the general linear group. We also show that for classical groups our definition gives symplectic and orthogonal representations of quivers with involution inverting the direction of arrows.
Let be a connected reductive subgroup of a complex connected reductive group . Fix maximal tori and Borel subgroups of and . Consider the cone generated by the pairs of strictly dominant characters such that is a submodule of . We obtain a bijective parametrization of the faces of as a consequence of general results on GIT-cones. We show how to read the inclusion of faces off this parametrization.