Tuple regularity and $k$-ultrahomogeneity for finite groups

Abstract

For $k, \ell \in \mathbb{N}$, we introduce the concepts of $k$-ultrahomogeneity and $\ell$-tuple regularity for finite groups. Inspired by analogous concepts in graph theory, these form a natural generalization of homogeneity, which was studied by Cherlin and Felgner and Li as well as automorphism transitivity, which was investigated by Zhang. Additionally, these groups have an interesting algorithmic interpretation. We classify the $k$-ultrahomogeneous and $\ell$-tuple regular finite groups for $k, \ell \geq 2$. In particular, we show that every 2-tuple regular finite group is ultrahomogeneous.