Sur les opérations holomorphes du groupe additif complexe sur l'espace de deux variables complexes
Sur les orbites fermées des groupes algébriques réductifs.
Sur les représentations p-adiques des corps locaux multidmensionelles attachés aux groupes formels.
Sur l'idéal du cône autocommutant des super algèbres de Lie basiques classiques et étranges
Cet article démontre que le cône de la partie impaire d’une super algèbre de Lie basique classique ou étrange défini par les équations est réduit.
Surfaces réglées non compactes et groupes discrets.
Symétries des surfaces rationnelles génériques.
Symmetric and exterior powers of homogeneous vector bundles.
Symmetric Functions, Conjugacy Classes and the Flag Variety.
Symmetric spaces associated to split algebraic groups over a local field.
Systèmes de Honda des schémas en -vectoriels
Tamagawa number of reductive algebraic groups
Tame stacks in positive characteristic
We introduce and study a class of algebraic stacks with finite inertia in positive and mixed characteristic, which we call tame algebraic stacks. They include tame Deligne-Mumford stacks, and are arguably better behaved than general Deligne-Mumford stacks. We also give a complete characterization of finite flat linearly reductive schemes over an arbitrary base. Our main result is that tame algebraic stacks are étale locally quotient by actions of linearly reductive finite group schemes.
Tate duality and wild ramification.
Tensor Products and Discriminants of Unital Quadratic Forms over Commutative Rings.
The additive group actions on -homology planes
In this article, we prove that a -homology plane with two algebraically independent -actions is isomorphic to either the affine plane or a quotient of an affine hypersurface in the affine -space via a free -action, where is the order of a finite group .
The algebraic fundamental group of a reductive group scheme over an arbitrary base scheme
We define the algebraic fundamental group π 1(G) of a reductive group scheme G over an arbitrary non-empty base scheme and show that the resulting functor G↦ π1(G) is exact.
The automorphism group of linear sections of the Grassmannians .
The bar automorphism in quantum groups and geometry of quiver representations
Two geometric interpretations of the bar automorphism in the positive part of a quantized enveloping algebra are given. The first is in terms of numbers of rational points over finite fields of quiver analogues of orbital varieties; the second is in terms of a duality of constructible functions provided by preprojective varieties of quivers.
The Brauer category and invariant theory
A category of Brauer diagrams, analogous to Turaev’s tangle category, is introduced, a presentation of the category is given, and full tensor functors are constructed from this category to the category of tensor representations of the orthogonal group O or the symplectic group Sp over any field of characteristic zero. The first and second fundamental theorems of invariant theory for these classical groups are generalised to the category theoretic setting. The major outcome is that we obtain presentations...
The canonical combinatorial sheaf associated to an involution of a semisimple adjoint group.