English

Nonabelian $H^2$ with coefficients in a group and with coefficients in a crossed module

Group Theory 2026-03-31 v3 Algebraic Geometry Category Theory K-Theory and Homology

Abstract

In this note, following Dedecker and Debremaeker, we extend the cohomology exact sequence for nonabelian H1H^1, using nonabelian H2H^2 with coefficients in crossed modules.

Keywords

Cite

@article{arxiv.1608.07366,
  title  = {Nonabelian $H^2$ with coefficients in a group and with coefficients in a crossed module},
  author = {Mikhail Borovoi},
  journal= {arXiv preprint arXiv:1608.07366},
  year   = {2026}
}

Comments

V.1: 9 pages, v.3: 10 pages, with appendices