# Computing normalisers of highly intransitive permutation groups

GRAW02 - Computational and algorithmic methods

In general, there is no known polynomial-time algorithm for computing the normaliser $N_{S_n}(H)$ of a given group $H \leq S_n$. In this talk, we will consider the case when $H$ is a subdirect product of permutation isomorphic non-abelian simple groups. In contrast to the case with abelian simple groups, where only practical improvements have been made, here we show that $N_{S_n}(H)$ can be computed in polynomial time.

This talk is part of the Isaac Newton Institute Seminar Series series.