On contractibility of the Orbit Space of a G-Poset of Brauer Pairs

Abstract

Given ap-blockbof a finite groupG, we show that theG-poset of Brauer pairs strictly containing (1,b) has contractibleG-orbit space. A similar result is proved for certainG-posets ofp-subgroups. Both results generalise P. Symonds' verification of a conjecture of P. Webb.