Characters of the Nullcone.
Composantes irréductibles de la variété commutante nilpotente d’une algèbre de Lie symétrique semi-simple
Soit une involution de l’algèbre de Lie semi-simple de dimension finie et la décomposition de Cartan associée. La variété commutante nilpotente de l’algèbre de Lie symétrique est formée des paires d’éléments nilpotents de tels que . Il est conjecturé que cette variété est équidimensionnelle et que ses composantes irréductibles sont indexées par les orbites d’éléments -distingués. Cette conjecture a été démontrée par A. Premet dans le cas avec . Dans ce travail, nous la prouvons...
Gradedness of the set of rook placements in
A rook placement is a subset of a root system consisting of positive roots with pairwise non-positive inner products. To each rook placement in a root system one can assign the coadjoint orbit of the Borel subgroup of a reductive algebraic group with this root system. Degenerations of such orbits induce a natural partial order on the set of rook placements. We study combinatorial structure of the set of rook placements in with respect to a slightly different order and prove that this poset is...
Higher symmetries of the Laplacian via quantization
We develop a new approach, based on quantization methods, to study higher symmetries of invariant differential operators. We focus here on conformally invariant powers of the Laplacian over a conformally flat manifold and recover results of Eastwood, Leistner, Gover and Šilhan. In particular, conformally equivariant quantization establishes a correspondence between the algebra of Hamiltonian symmetries of the null geodesic flow and the algebra of higher symmetries of the conformal Laplacian. Combined...
Polynômes de Joseph et représentation de Springer
Quadratic and homogeneous Hamilton-Poisson systems on .
Quantization commutes with reduction in the non-compact setting: the case of holomorphic discrete series
In this paper we show that the multiplicities of holomorphic discrete series representations relative to reductive subgroups satisfy the credo “quantization commutes with reduction”.
Series of nilpotent orbits.
The closure diagrams for nilpotent orbits of real forms of and .
Whittaker models, nilpotent orbits and the asymptotics of Harish-Chandra modules