On Contractibility of the Orbit Space of aG-Poset of Brauer Pairs

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. Symondsʹ verification of a conjecture of P. Webb.