Derived induction theory for the K-theory of modular group algebras

Fuente: arXiv
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Main Author: Vogeli, Chase
Format: Preprint
Published: 2025
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author Vogeli, Chase
author_facet Vogeli, Chase
contents We prove an induction theorem for the higher algebraic K-groups of group algebras $kG$ of finite groups $G$ over characteristic $p$ finite fields $k$. For a certain class of finite groups, which we call $p$-isolated, this reduces calculations to calculations for their $p$-subgroups. We do so by showing that the stable module categories of $kH$ as $H$ ranges over subgroups of $G$ assemble into a categorical Green functor, which results in a spectral Green functor structure on K-theory. By general induction theory, this reduces proving a spectrum-level induction statement to proving an induction statement on $π_0$ Green functors, which we accomplish using modular representation theory. For $p$-isolated groups with Sylow $p$-subgroups of order $p$, we produce explicit new calculations of K-groups.
format Preprint
id arxiv_https___arxiv_org_abs_2510_25763
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Derived induction theory for the K-theory of modular group algebras
Vogeli, Chase
K-Theory and Homology
Algebraic Topology
19D50, 55P91, 19A22, 20C20
We prove an induction theorem for the higher algebraic K-groups of group algebras $kG$ of finite groups $G$ over characteristic $p$ finite fields $k$. For a certain class of finite groups, which we call $p$-isolated, this reduces calculations to calculations for their $p$-subgroups. We do so by showing that the stable module categories of $kH$ as $H$ ranges over subgroups of $G$ assemble into a categorical Green functor, which results in a spectral Green functor structure on K-theory. By general induction theory, this reduces proving a spectrum-level induction statement to proving an induction statement on $π_0$ Green functors, which we accomplish using modular representation theory. For $p$-isolated groups with Sylow $p$-subgroups of order $p$, we produce explicit new calculations of K-groups.
title Derived induction theory for the K-theory of modular group algebras
topic K-Theory and Homology
Algebraic Topology
19D50, 55P91, 19A22, 20C20
url https://arxiv.org/abs/2510.25763