Journal of Lie Theory Vol. 13, No. 1, pp. 271278 (2003) 

Sousgroupes elliptiques de groupes lin{é}aires sur un corps valu{é}Anne ParreauAnne ParreauLaboratoire Emile Picard, UMR 5580 du CNRS, Université Paul Sabatier, UFR MIG 118, route de Narbonne, 31062 Toulouse Cedex 04, France. parreau@picard.upstlse.fr Abstract: Let $n$ be a positive integer and $\mathbb{F}$ be a valuated field. We prove the following result: Let $\Gamma$ be a subgroup of ${\rm GL}_n(\mathbb{F})$ generated by a bounded subset, such that every element of $\Gamma$ belongs to a bounded subgroup. Then $\Gamma$ is bounded. This implies the following. Let $G$ be a connected reductive group over $\mathbb{F}$. Suppose that $\mathbb{F}$ is henselian (e.g.\ complete) and either that $G$ is almost split over $\mathbb{F}$, or that the valuation of $\mathbb{F}$ is discrete and $\mathbb{F}$ has perfect (e.g. finite) residue class field. Let $\Delta$ be its (extended) BruhatTits building. Let $x_0$ be any point in $\Delta$ and $\overline{\Delta}$ be the completion of $\Delta$. Let $\Gamma$ be a subgroup of $G$ generated by $S$ with $S.x_0$ bounded, such that every element of $\Gamma$ fixes a point in $\overline{\Delta}$, then $\Gamma$ has a global fixed point in $\overline{\Delta}$. Full text of the article:
Electronic fulltext finalized on: 22 Nov 2002. This page was last modified: 3 Jan 2003.
© 2002 Heldermann Verlag
