Lean4
/-- Bicategory structure on `Cat` -/
instance bicategory : Bicategory.{max v u, max v u} Cat.{v, u}
where
Hom C D := C ⥤ D
id C := 𝟭 C
comp F G := F ⋙ G
homCategory := fun _ _ => Functor.category
whiskerLeft {_} {_} {_} F _ _ η := whiskerLeft F η
whiskerRight {_} {_} {_} _ _ η H := whiskerRight η H
associator {_} {_} {_} _ := Functor.associator
leftUnitor {_} _ := Functor.leftUnitor
rightUnitor {_} _ := Functor.rightUnitor
pentagon := fun {_} {_} {_} {_} {_} => Functor.pentagon
triangle {_} {_} {_} := Functor.triangle