Anticommutativity and the triangular lemma
Category Theory
2020-11-03 v2
Abstract
For a variety , it has been recently shown that binary products commute with arbitrary coequalizers locally, i.e., in every fibre of the fibration of points , if and only if Gumm's shifting lemma holds on pullbacks in . In this paper, we establish a similar result connecting the so-called triangular lemma in universal algebra with a certain categorical condition. In particular, we show that this anticommutativity and its local version are Mal'tsev conditions, the local version being equivalent to the triangular lemma on pullbacks. As a corollary, every locally anticommutative variety has directly decomposable congruence classes in the sense of Duda, and the converse holds if is idempotent.
Keywords
Cite
@article{arxiv.2008.00486,
title = {Anticommutativity and the triangular lemma},
author = {Michael Hoefnagel},
journal= {arXiv preprint arXiv:2008.00486},
year = {2020}
}
Comments
18 pages