English

Spans of cospans

Category Theory 2018-02-05 v2

Abstract

We discuss the notion of a span of cospans and define, for them, horizonal and vertical composition. These compositions satisfy the interchange law if working in a topos C\mathbf{C} and if the span legs are monic. A bicategory is then constructed from C\mathbf{C}-objects, C\mathbf{C}-cospans, and doubly monic spans of C\mathbf{C}-cospans. The primary motivation for this construction is an application to graph rewriting.

Keywords

Cite

@article{arxiv.1611.07886,
  title  = {Spans of cospans},
  author = {Daniel Cicala},
  journal= {arXiv preprint arXiv:1611.07886},
  year   = {2018}
}
R2 v1 2026-06-22T17:02:35.173Z