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

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.)

- Robert Paré,
*Retrocells*, arXiv:2306.06436.

Created on June 22, 2023 at 19:41:43. See the history of this page for a list of all contributions to it.