A reference for categorical structures on $\mathbf{Poly}$
David I. Spivak
Published: 2022/2/1
Abstract
In this document, we collect a list of categorical structures on the category $\mathbf{Poly}$ of polynomial functors. There is no implied claim that this list is in any way complete. It includes: infinitely many monoidal structures, all but one of which is symmetric, closed, and distributes over $+$, several of which interact duoidally; it also includes a right-coclosure and two indexed left coclosures; it also includes various adjunctions of which $\mathbf{Poly}$ is a part, including the free monad and cofree comonad and their interaction with various monoidal structures.