English

Beyond a question of Markus Linckelmann

Group Theory 2021-09-30 v3

Abstract

In the 2002 Durham Symposium, Markus Linckelmann [1] conjectured the existence of a regular central k*-extension of the full subcategory over the selfcentralizing Brauer pairs of the Frobenius P-category F_{(b,G)} associated with a block b of defect group P of a finite group G, which would include, as k*-automorphism groups of the objects, the k*-groups associated with the automizers of the corresponding selfcentralizing Brauer (b,G)-pairs, introduced in [3, 6.6]; as a matter of fact, in this question the selfcentralizing Brauer pairs can be replaced by the nilcentralized Brauer pairs, still getting a positive answer. But the condition on the k*-automorphism groups of the objects is not precise enough to guarantee the uniqueness of a solution, as showed by Sejong Park in [2, Theorem 1.3]. This uniqueness depends on the folder structure [5,~Section~2] associated with F_{(b,G)} in [4,~Theorem~11.32], and here we prove the existence and the uniqueness of such a regular central k*-extension for any folded Frobenius P-category.

Keywords

Cite

@article{arxiv.1507.04278,
  title  = {Beyond a question of Markus Linckelmann},
  author = {Lluis Puig},
  journal= {arXiv preprint arXiv:1507.04278},
  year   = {2021}
}

Comments

This paper precises and generalizes the previous preprint "Affirmative answer to a question of Linckelmann"

R2 v1 2026-06-22T10:12:29.785Z