Yang-Baxter extremal characters of wreath products of finite groups with the infinite symmetric group

TL;DR

This paper characterizes the parameters corresponding to extremal Yang-Baxter characters of wreath products of finite groups with the infinite symmetric group, linking representation theory, solutions to the Yang-Baxter equation, and extremal characters.

Contribution

It provides a precise characterization of the parameter subset that yields extremal Yang-Baxter characters for these wreath product groups.

Findings

Identifies the parameter subset for extremal characters

Establishes a bijection between extremal characters and parameters

Connects Yang-Baxter solutions with representation theory of wreath products

Abstract

Let $T$ be a finite group. To a representation $\pi$ of $T$ and an involutive solution of the Yang-Baxter equation (an $R$-matrix) verifying the "extended" reflection equation, we associate a character and a representation of the wreath product $G:=T\wr \mathfrak{S}_\infty$. The set of extremal characters of $G$ is in bijection with a continuous set of parameters. In this article, we characterize exactly what subset of parameters does correspond to an extremal Yang-Baxter character of $G$.