Finite $p$-groups of class two with a large multiple holomorph

Abstract

Let $G$ be any group. The quotient group $T(G)$ of the multiple holomorph by the holomorph of $G$ has been investigated for various families of groups $G$. In this paper, we shall take $G$ to be a finite $p$-group of class two for any odd prime $p$, in which case $T(G)$ may be studied using certain bilinear forms. For any $n\ge 4$, we exhibit examples of $G$ of order $p^{n+\left(\genfrac{}{}{0ex}{}{n}{2}\right)}$ such that $T(G)$ contains a subgroup isomorphic to \begin{equation*} \operatorname{GL}_n(\mathbb{F}_p) \times \operatorname{GL}_{\binom{n}{2}-n}(\mathbb{F}_p).\end{equation*} For finite $p$-groups $G$, the prime factors of the order of $T(G)$ which are known so far all came from $p(p-1)$. Our examples show that the order of $T(G)$ can have other prime factors as well. In fact, we can embed any finite group into $T(G)$ for a suitable choice of $G$.

20 pages, added Definition 2.2 and a few small edits

References in corpus (3)

• Bi-skew braces and Hopf Galois structures
• The multiple holomorph of a finitely generated abelian group
• Brace blocks from bilinear maps and liftings of endomorphisms

Cited by in corpus (2)

• Normalizer Quotients of Symmetric Groups and Inner Holomorphs
• Finite $p$-groups of class two with a small multiple holomorph