2 problems

Let $G$ be a finite group, and consider an open interval in the subgroup lattice of $G$. Shareshian's conjecture. Every such open interval has the same homotopy type as a wedge of…

Let $G$ be a finite solvable group, and let $L(G)$ denote its subgroup lattice. Choose a chief series … A complement to a subgroup $N$ is a subgroup $H$ with $HN=G$ and $H\cap N=1$…