Commit 2026-09-30 10:44 851d2845
View on Github →feat(CategoryTheory): express monoidal pentagons using quadrifunctors (#43008) Expresses the monoidal pentagon and triangle as equalities of natural transformations between quadrifunctors and bifunctors, and adds a corresponding MonoidalCategory.ofBifunctor constructor. This resolves the quadrifunctor API TODO in Mathlib/CategoryTheory/Monoidal/Multifunctor.lean.