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Divisibility of Character Values of Representations of Coxeter Groups

Jyotirmoy Ganguly, Rohit Joshi

TL;DR

The paper analyzes the asymptotic divisibility of irreducible character values across infinite families of irreducible Coxeter groups by introducing the statistic $\mathscr{L}(\mathscr{C}(G_n, G_0), g, d)$. It shows that for types $A_n$, $B_n$, and $D_n$ the proportion of irreducible characters with values divisible by a fixed $d$ tends to $1$, while for dihedral groups $I_2(m)$ the limit is computed explicitly in terms of $m$, $l$, and $d$, including 2-adic conditions. The results are established through detailed analyses of conjugacy classes and irreducible representations (notably bipartitions for $\mathbb{B}_n$ and induced representations), together with integrality arguments involving centralizers and explicit character formulas. By handling Hyperoctahedral, Demi-Hyperoctahedral, and Dihedral families, the work provides a unified framework for the divisibility behavior of character values across all infinite Coxeter families, with concrete limits depending on the group family and chosen elements.

Abstract

Let $d$ be a positive integer. We study the proportion of irreducible characters of infinite families of irreducible Coxeter groups whose values evaluated on a fixed element $g$ are divisible by $d$. For Coxeter groups of types $A_n, B_n$ and $D_n$, the proportion tends to $1$ as $n$ approaches infinity. For Dihedral groups, which are Coxeter groups of type $I_2(n)$, we compute the limit of the proportion.

Divisibility of Character Values of Representations of Coxeter Groups

TL;DR

The paper analyzes the asymptotic divisibility of irreducible character values across infinite families of irreducible Coxeter groups by introducing the statistic . It shows that for types , , and the proportion of irreducible characters with values divisible by a fixed tends to , while for dihedral groups the limit is computed explicitly in terms of , , and , including 2-adic conditions. The results are established through detailed analyses of conjugacy classes and irreducible representations (notably bipartitions for and induced representations), together with integrality arguments involving centralizers and explicit character formulas. By handling Hyperoctahedral, Demi-Hyperoctahedral, and Dihedral families, the work provides a unified framework for the divisibility behavior of character values across all infinite Coxeter families, with concrete limits depending on the group family and chosen elements.

Abstract

Let be a positive integer. We study the proportion of irreducible characters of infinite families of irreducible Coxeter groups whose values evaluated on a fixed element are divisible by . For Coxeter groups of types and , the proportion tends to as approaches infinity. For Dihedral groups, which are Coxeter groups of type , we compute the limit of the proportion.
Paper Structure (11 sections, 16 theorems, 67 equations, 1 figure)

This paper contains 11 sections, 16 theorems, 67 equations, 1 figure.

Key Result

Theorem 1.1

For any positive integers $d$ and $k$ and an element $g\in \mathbb{B}_k$, we have

Figures (1)

  • Figure 1: The figure shows an embedding of $\Delta_3=P_1P_3P_5$ inside $\Delta_6$.

Theorems & Definitions (28)

  • Theorem 1.1
  • Theorem 1.2
  • Theorem 2.1
  • Theorem 2.2
  • Lemma 3.1
  • Lemma 3.2
  • proof
  • proof : Proof of \ref{['mt']}
  • Theorem 4.1
  • Lemma 4.2
  • ...and 18 more