Natural Associativity without the Pentagon condition
Abstract
Description
A premonoidal category is equipped only with a bifunctor and a natural isomorphism for associativity. We introduce a (deformation) natural automorphism representing the deviation from the Pentagon condition. We uncover a binary tree representation for all diagrams involving associativity natural isomorphisms and (deformation) natural automorphisms and provide a link to permutations and linear orderings. This leads to other notions of premonoidalness. We define these notions and prove coherence results for each.
49 pages, 54 figures (requires diagram.sty) Refinement of definitions (and incorporation of related new material) in line with recent developments by the author. In particular the new definition of a pseudomonoidal category introduced in a recent paper called Braid Premonoidal Coherence. (A few minor typos corrected.)
49 pages, 54 figures (requires diagram.sty) Refinement of definitions (and incorporation of related new material) in line with recent developments by the author. In particular the new definition of a pseudomonoidal category introduced in a recent paper called Braid Premonoidal Coherence. (A few minor typos corrected.)