Character theory and Euler characteristic for orbispaces and infinite groups

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Lück, Wolfgang, Patchkoria, Irakli, Schwede, Stefan
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913553649238016
author Lück, Wolfgang
Patchkoria, Irakli
Schwede, Stefan
author_facet Lück, Wolfgang
Patchkoria, Irakli
Schwede, Stefan
contents Given a discrete group $G$ with a finite model for $\underline{E}G$, we study $K(n)^*(BG)$ and $E^*(BG)$, where $K(n)$ is the $n$-th Morava $K$-theory for a given prime and $E$ is the height $n$ Morava $E$-theory. In particular we generalize the character theory of Hopkins, Kuhn and Ravenel who studied these objects for finite groups. We give a formula for a localization of $E^*(BG)$ and the $K(n)$-theoretic Euler characteristic of $BG$ in terms of centralizers. In certain cases these calculations lead to a full computation of $E^*(BG)$, for example when $G$ is a right angled Coxeter group, and for $G=SL_3(\mathbb{Z})$. We apply our results to the mapping class group $Γ_\frac{p-1}{2}$ for an odd prime $p$ and to certain arithmetic groups, including the symplectic group $Sp_{p-1}(\mathbb{Z})$ for an odd prime $p$ and $SL_2(\mathcal{O}_K)$ for a totally real field $K$.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14510
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Character theory and Euler characteristic for orbispaces and infinite groups
Lück, Wolfgang
Patchkoria, Irakli
Schwede, Stefan
Algebraic Topology
Group Theory
K-Theory and Homology
Primary: 55P42, 55R35. Secondary: 55P91, 19L, 20F65
Given a discrete group $G$ with a finite model for $\underline{E}G$, we study $K(n)^*(BG)$ and $E^*(BG)$, where $K(n)$ is the $n$-th Morava $K$-theory for a given prime and $E$ is the height $n$ Morava $E$-theory. In particular we generalize the character theory of Hopkins, Kuhn and Ravenel who studied these objects for finite groups. We give a formula for a localization of $E^*(BG)$ and the $K(n)$-theoretic Euler characteristic of $BG$ in terms of centralizers. In certain cases these calculations lead to a full computation of $E^*(BG)$, for example when $G$ is a right angled Coxeter group, and for $G=SL_3(\mathbb{Z})$. We apply our results to the mapping class group $Γ_\frac{p-1}{2}$ for an odd prime $p$ and to certain arithmetic groups, including the symplectic group $Sp_{p-1}(\mathbb{Z})$ for an odd prime $p$ and $SL_2(\mathcal{O}_K)$ for a totally real field $K$.
title Character theory and Euler characteristic for orbispaces and infinite groups
topic Algebraic Topology
Group Theory
K-Theory and Homology
Primary: 55P42, 55R35. Secondary: 55P91, 19L, 20F65
url https://arxiv.org/abs/2410.14510