nLab retrocell

Idea

In a double category $C$ with companions, a retrocell is …

Example

In the double category of spans, a retrocell boils down to a morphism of spans, where the source span is the pullback of the original source span along the corresponding horizontal arrow. (Paré, §5.)

References

• Robert Paré, Retrocells, Theory and Applications of Categories, Vol. 40, 2024, No. 5, pp 130-179. [TAC, arXiv:2306.06436]