Showing math.CTShow all
3 papers · 1 filter
math.CT2025
Multiple categories of general quintets
Marco Grandis, Robert Paré
We construct various multiple categories, based on generalised Ehresmann quintets. The main construction is a multiple category whose objects are all the `lax' multiple categories;…
math.CT2024
Taut functors and the difference operator
Robert Paré
We establish a calculus of differences for taut endofunctors of the category of sets, analogous to the classical calculus of finite differences for real valued functions. We study…
math.CT2023
Retrocells
Robert Paré
The notion of retrocell in a double category with companions is introduced and its basic properties established. Explicit descriptions in some of the usual double categories are gi…