The Center Conjecture for thick spherical buildings

Abstract

In this paper we show that a convex subcomplex of a spherical building of type E6, E7 or E8 is a subbuilding or the automorphisms of the subcomplex fix a point on it. Together with previous results of M\"uhlherr-Tits, and Leeb and the author, this completes the proof of Tits' Center Conjecture for spherical buildings without factors of type H4, in particular, for thick spherical buildings.