English

A Note on the Eilenberg-Mac Lane Isomorphism for Quadratic Forms

Category Theory 2025-12-02 v2

Abstract

We give an elementary proof of the Eilenberg-Mac Lane trace isomorphism between the third 2-abelian cohomology group and quadratic forms. Our approach yields explicit constructions and we characterize when quadratic forms can be expressed as traces of bilinear forms for arbitrary coefficient groups.

Keywords

Cite

@article{arxiv.2507.15726,
  title  = {A Note on the Eilenberg-Mac Lane Isomorphism for Quadratic Forms},
  author = {César Galindo},
  journal= {arXiv preprint arXiv:2507.15726},
  year   = {2025}
}

Comments

15 pages. Final version. Accepted in PAMS

R2 v1 2026-07-01T04:11:38.367Z