Random endomorphisms of spherical reflection groups

Abstract

The goal of this paper is to understand the set $\mathrm{End}(W)$ of endomorphisms of an irreducible spherical reflection group $W$. We do this in two ways: numerically, by deriving an explicit formula for $|\mathrm{End}(W)|$; and probabilistically, by exploring the question \textit{what does a random endomorphism of $W$ look like?} For example, we show that as $n\to \infty$ the probability that a random endomorphism of $W_n$ is an automorphism tends to $\frac{1}{2}$ if $W_n=C_{2n}$ or $D_n$, to $\frac{1}{4}$ if $W_n=C_{2n+1}$, and to $1$ if $W_n=A_n.$

arXiv comment22 pages, 3 figures