2 problems

Let $G_{d,q}$ be the covering graph of the face-lattice of the finite projective space $\operatorname{PG}(d,q)$ of dimension $d$ and order $q$, and let $p(G_{d,q})$ denote the conn…

Let ${\mit\Gamma}$ be a modular graph. For an orbit $Q$ of ${\mit\Gamma}$, let ${\mit\Gamma}/Q$ be the corresponding quotient graph, and let $\tau({\mit\Gamma},h;V,c)$ denote the o…