surface diagrams of interaction laws

Consider a 2-monoid in a monoidal 2-category. An interaction law between a monoid and a comonoid on the 2-monoid is given by the following surface diagrams.

References.

• Interaction Laws of Monads and Comonads (Katsumata, Rivas, Uustalu, 2019)

Tags: surface diagrams, monoidal bicategory.