I'm trying to find out whether the following graph has a name: Let $W$ be an $n$-dimensional vector space over $GF(q)$. The vertices of the graph are all the subspaces of $W$. Two subspaces $W_1$ and $W_2$ are connected iff both $|\dim(W_1)-\dim(W_2)|=1$, and either $W_1\subset W_2$ or $W_2\subset W_1$. This is the Hasse diagram of subspace inclusion. I was wondering whether this graph already has a name I can refer to.