Parity complexes redux
Category Theory
2026-05-12 v1
Abstract
We fix the notion of parity complex by a judicious selection from among the axioms originally considered by Street. We show that parity complexes so defined, together with the morphisms of parity complexes defined by Verity, form a category equivalent to the category of strong Steiner complexes (n\'es augmented directed complexes with strongly loop-free unital bases). To this end, we isolate the purely combinatorial structure possessed by the bases of free augmented directed complexes. This analysis reveals the essential advantage of Steiner's formalism to be that the role of subsets in Street's formalism is played instead by multisets.
Cite
@article{arxiv.2605.09427,
title = {Parity complexes redux},
author = {Alexander Campbell},
journal= {arXiv preprint arXiv:2605.09427},
year = {2026}
}
Comments
17 pages. Written for Ross Street's 80th birthday