2 problems

Let a central digraph be a digraph of the type considered in the paper, and let its size be the number of elements in the underlying central groupoid. Let the natural central digra…

Let $k$ be a positive integer, let $c$ be the multiplicative order, and let $w_1,w_2$ be units modulo $k$. For each unit $w$, let $G(k,c,w)$ denote the corresponding metacyclic cen…