A simultaneous variant of the Hall-Paige theorem and applications

Abstract

For $k\geq 1$ , we say that a finite group $G$ satisfies property $\mathcal P_k$ if, for every $\beta_1,\ldots,\beta_k\in\operatorname{Aut}(G)$, there exists a bijection $f$ of $G$ such that each map $g\mapsto \beta_i(g)f(g)$ is a bijection. For $k=1$ this is equivalent to the classical Hall--Paige complete mapping property. We prove that if $p$ is the smallest prime divisor of $|G|$, then $G$ satisfies $\mathcal P_k$ for every $k<p-1$ and we show that this bound is sharp. For finite abelian $p$-groups, the bijection $f$ may moreover be chosen to be an automorphism, and for noncyclic homocyclic $p$-groups this remains true for $k=p-1$. Finally, we interpret $\mathcal P_k$ in terms of common transversals and common orthogonal mates of Latin squares generated from automorphisms and the Cayley table of a finite group $G$.