On the representations of GL(2). I. E-factors and n-closeness.
On the Schur Indices of Characters of GL (2, q) and GL (3, q).
On the Schur Multipliers of Steinberg and Chevalley Groups over Commutative Rings.
On the set of orbits for a Borel subgroup.
On the squares of sets of linear groups
On the stability of subgroup actions on certain quasihomogeneous -varieties.
On the structure of algebraic groups over global fields.
On the Top Betti Number of Subgroups of SL(n,Z).
On the translation functors for a semisimple algebraic group.
On the Unipotent Characters of the Exceptional Groups Over Finite Fields.
On tilting modules for algebraic groups.
On unipotent blocks and their ordinary characters.
On varieties of Hilbert type
A variety over a field is of Hilbert type if is not thin. We prove that if is a dominant morphism of -varieties and both and all fibers , , are of Hilbert type, then so is . We apply this to answer a question of Serre on products of varieties and to generalize a result of Colliot-Thélène and Sansuc on algebraic groups.
On Virtual Properties and Group Extensions.
On volumes of arithmetic quotients of
We apply G. Prasad’s volume formula for the arithmetic quotients of semi-simple groups and Bruhat-Tits theory to study the covolumes of arithmetic subgroups of . As a result we prove that for any even dimension there exists a unique compact arithmetic hyperbolic -orbifold of the smallest volume. We give a formula for the Euler-Poincaré characteristic of the orbifolds and present an explicit description of their fundamental groups as the stabilizers of certain lattices in quadratic spaces. We...
Opérateur de torsion dans et
Orbit measures, random matrix theory and interlaced determinantal processes
A connection between representation of compact groups and some invariant ensembles of hermitian matrices is described. We focus on two types of invariant ensembles which extend the gaussian and the Laguerre Unitary ensembles. We study them using projections and convolutions of invariant probability measures on adjoint orbits of a compact Lie group. These measures are described by semiclassical approximation involving tensor and restriction multiplicities. We show that a large class of them are determinantal....
Orbites d'un groupe algébrique dans l'espace des idéaux rationnels d'une algèbre enveloppante
Orbits, Invariants, and Representations Associated to Involutions of Reductive Groups.
Orbits of the Weyl group and a theorem of DeConcini and Procesi