Hopf measuring comonoids and enrichment
arXiv:1509.07632 · doi:10.1112/plms.12064
Abstract
We study the existence of universal measuring comonoids for a pair of monoids , in a braided monoidal closed category, and the associated enrichment of a category of monoids over the monoidal category of comonoids. In symmetric categories, we show that if is a bimonoid and is a commutative monoid, then is a bimonoid; in addition, if is a cocommutative Hopf monoid then always is Hopf. If is a Hopf monoid, not necessarily cocommutative, then is Hopf if the fundamental theorem of comodules holds; to prove this we give an alternative description of the dualizable -comodules and use the theory of Hopf (co)monads. We explore the examples of universal measuring comonoids in vector spaces and graded spaces.
30 pages. Version 2: re-arrangement of material; expansion of previous section 6, splitting into current sections 6,7,8; fix of graded algebras example, section 11; appendix removed; other minor fixes and edits