Spans of cospans

Daniel Cicala

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arXiv · 1611.07886

Spans of cospans

Daniel Cicala

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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 $\mathbf{C}$ and if the span legs are monic. A bicategory is then constructed from $\mathbf{C}$-objects, $\mathbf{C}$-cospans, and doubly monic spans of $\mathbf{C}$-cospans. The primary motivation for this construction is an application to graph rewriting.

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Daniel Cicala. 2016-11-23. Spans of cospans. https://arxiv.org/abs/1611.07886

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