Independence and strong independence complexes of finite groups

Abstract

Let $G$ be a finite group. In 2024, Cameron introduced two different concepts of independence (namely independence and strong independence) for the subsets of $G$, yielding to the definition of two simplicial complexes whose vertices are the elements of $G$. The strong independence complex $\tilde\Sigma(G)$ turns out to be a subcomplex of the independence complex $\Sigma(G)$. We discuss several invariant properties related to these complexes and ask a number of questions inspired by our results and the examples we construct. We study then the particular case of complexes on finite abelian groups, giving a characterization of the finite groups realizing them. In conclusion, answering a question of Cameron, we classify all finite groups in which the two concepts of independence coincide.