Shigeo Koshitani

activity

20242026

collaborators

4 papers

math.RT2026

The Mathieu group $M_{12}$ vs $S L_{3} (3)$ in characteristic 3

Shigeo Koshitani, Tetsuro Okuyama

We prove that the principal $3$ -blocks of the Mathieu group $M_{12}$ and the special linear group $\SL_3(3)$ are splendidly Rickard equivalent, and hence derived equivalent,…

math.RT2026

A reciprocity theorem of Robinson-Benson-Webb for finite-dimensional symmetric algebras

Shigeo Koshitani

We generalize the reciprocity theorem of G.R.~Robinson, D. Benson and P. Webb between a finite group and its subgroup to the case of finite-dimensional {\it symmetric} algebras ove…

math.RT2025

Lifting Brauer indecomposability of a Scott module

Shigeo Koshitani, Ä°pek Tuvay

It is proven that if a finite group $G$ has a normal subgroup $H$ with $p^{'}$ -index (where $p$ is a prime) and $G / H$ is solvable, then for a $p$ -subgroup $P$ of $H$ , if the Scott $kH…

math.RT2024

Principal 2-blocks with wreathed defect groups up to splendid Morita equivalence

Shigeo Koshitani, Caroline Lassueur, Benjamin Sambale

We classify principal $2$ -blocks of finite groups $G$ with Sylow $2$ -subgroups isomorphic to a wreathed $2$ -group $C_{2^{n}} ≀ C_{2}$ with $n \geq 2$ up to Morita equivalence and up to…

The Mathieu group M12​ vs SL3​(3) in characteristic 3

A reciprocity theorem of Robinson-Benson-Webb for finite-dimensional symmetric algebras

Lifting Brauer indecomposability of a Scott module

Principal 2-blocks with wreathed defect groups up to splendid Morita equivalence

The Mathieu group $M_{12}$ vs $S L_{3} (3)$ in characteristic 3