English

Homology and cohomology via the partial group algebra

Group Theory 2023-11-10 v2 Rings and Algebras

Abstract

We study partial homology and cohomology from ring theoretic point of view via the partial group algebra KparG\mathbb{K}_{par}G. In particular, we link the partial homology and cohomology of a group GG with coefficients in an irreducible (resp. indecomposable) KparG\mathbb{K}_{par}G-module with the ordinary homology and cohomology groups of GG with in general non-trivial coefficients. Furthermore, we compare the standard cohomological dimension cd K(G)cd_{ \ \mathbb{K}}(G) (over a field K\mathbb{K}) with the partial cohomological dimension cd Kpar(G)cd_{ \ \mathbb{K}}^{par}(G) (over K\mathbb{K}) and show that cd Kpar(G)cd K(G)cd_{ \ \mathbb{K}}^{par}(G) \geq cd_{ \ \mathbb{K}}(G) and that there is equality for G=ZG = \mathbb{Z}.

Keywords

Cite

@article{arxiv.2006.10173,
  title  = {Homology and cohomology via the partial group algebra},
  author = {Marcelo Muniz Alves and Mikhailo Dokuchaev and Dessislava H. Kochloukova},
  journal= {arXiv preprint arXiv:2006.10173},
  year   = {2023}
}

Comments

The statement of Corollary C was changed and Section 6 was basically rewritten as several of the results there were not correct. Section 7 was removed. Some other small changes were made through the text