A Suspension Lemma for Bounded Posets
arXiv:math/9703212
Abstract
Let and be bounded posets. In this note, a lemma is introduced that provides a set of sufficient conditions for the proper part of being homotopy equivalent to the suspension of the proper part of~. An application of this lemma is a unified proof of the sphericity of the higher Bruhat orders under both inclusion order (a known proved earlier by Ziegler) and single step inclusion order (which was not previously known).