Permutation groups, pattern involvement, and Galois connections

Abstract

There is a connection between permutation groups and permutation patterns: for any subgroup $G$ of the symmetric group $S_{\ell }$ and for any $n\ge \ell$, the set of $n$-permutations involving only members of $G$ as $\ell$-patterns is a subgroup of $S_n$. Making use of the monotone Galois connection induced by the pattern avoidance relation, we characterize the permutation groups that arise via pattern avoidance as automorphism groups of relations of a certain special form. We also investigate a related monotone Galois connection for permutation groups and describe its closed sets and kernels as automorphism groups of relations.

arXiv comment24 pages, 1 figure, typos corrected, some arguments clarified, results unchanged