Monoidal bicategories and Hopf algebroids (Q1362171)

This paper investigates the theory of monoidal bicategories, particularly Gray monoids. The main example is a monoidal bicategory of enriched categories over a suitably complete braided monoidal category. In particular, the paper studies the class of autonomous pseudomonoids. This is a class of weak monoid objects; it includes autonomous monoidal categories, Hopf algebras and Hopf algebroids (`Hopf algebras with several objects'). There is also some material on Hopf opalgebroids, where the `several object' idea is applied to the coalgebra structure rather than the algebra structure.