On Group bijections $\varphi$ with $\varphi (B)=A$ and $\forall a\in B,a\varphi (a)\notin A$

Yahya Ould Hamidoune

A {\em Wakeford pairing} from $S$ onto $T$ is a bijection $\varphi :S\to T$ such that $x\varphi (x)\notin T,$ for every $x\in S.$ The number of such pairings will be denoted by $\mu (S,T)$. Let $…