Add to ORKGIn this paper we prove a number of flatness results for centralizers of sections of a reductive group scheme over a general base scheme. To this end, we establish relative versions of the Jordan decomposition and establish the existence of an integral Springer isomorphism. Using our results, we obtain a canonical flattening stratification for the universal centralizer of a simply connected semisimple group scheme over a base of good characteristic. We also investigate the structure of centralizers of nilpotent sections over general bases and establish some regularity properties of unipotent varieties over fields of small characteristic.Comment: 64 pages, comments welcome
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The Grothendieck-Serre conjecture predicts that every generically trivial torsor under a reductive g...
Our objects of study are aftine group schemes, finitely presented and flat, over a domain A. As in 1...
Let G be a simple algebraic group defined over an algebraically closed field k whose characteristic ...
The universal centralizer of a semisimple algebraic group is the family of centralizers of regular e...
Let G be a reductive group over an algebraically closed field k of separably good characteristic p>0...
AbstractLet G be a semisimple algebraic group over a field K whose characteristic is very good for G...
nouveau titre, addition d'une application à une équivalence de Satake dérivéeInternational audienceW...
Let $K$ be a field, let $X$ be a connected smooth $K$-scheme and let $G,H$ be two smooth connected $...
Let $R$ be a regular semilocal integral domain containing an infinite field $k$. Let $f\in R$ be an ...
Let $G$ be a reductive group over a field $k$ which is algebraically closedof characteristic $p \neq...
Let G be a connected reductive group over an algebraically closed field and W be its Weyl group. Ste...
We construct universal $G$-zips on good reductions of the Pappas-Rapoport splitting models for PEL-t...
Let $G$ be a connected reductive algebraic group over an algebraically closed field $\mathbf{k}$, an...
If R is a commutative ring, G is a nite group, and H is a subgroup of G, then the centralizer algeb...
Let G be a connected algebraic reductive group in types A, B, or D, and e be a nilpotent element of ...
The Grothendieck-Serre conjecture predicts that every generically trivial torsor under a reductive g...
Our objects of study are aftine group schemes, finitely presented and flat, over a domain A. As in 1...
Let G be a simple algebraic group defined over an algebraically closed field k whose characteristic ...