Ein neuer Zusammenhang zwischen einfachen Gruppen und einfachen Singularitäten.
Soient un groupe algébrique réductif connexe défini sur et l’endomorphisme de Frobenius correspondant. Soit un automorphisme rationnel quasi-central de . Nous construisons ci-dessous l’équivalent des représentations de Gelfand-Graev du groupe , lorsque est unipotent et lorsqu’il est semi-simple. Nous montrons de plus que ces représentations vérifient des propriétés semblables à celles vérifiées par les représentations de Gelfand-Graev dans le cas connexe en particulier par rapport aux...
We give necessary and sufficient conditions for an orthogonal group defined over a global field of characteristic to contain a maximal torus of a given type.
We present a survey of results on word equations in simple groups, as well as their analogues and generalizations, which were obtained over the past decade using various methods: group-theoretic and coming from algebraic and arithmetic geometry, number theory, dynamical systems and computer algebra. Our focus is on interrelations of these machineries which led to numerous spectacular achievements, including solutions of several long-standing problems.
De Concini and Procesi have defined the wonderful compactification of a symmetric space where is a complex semisimple adjoint group and the subgroup of fixed points of by an involution . It is a closed subvariety of a Grassmannian of the Lie algebra of . In this paper we prove that, when the rank of is equal to the rank of , the variety is defined by linear equations. The set of equations expresses the fact that the invariant alternate trilinear form on vanishes on the -eigenspace...