-theorem BP_to_OBP_faithful:
- ∀S,T.∀f,g:arrows2 (category2_of_category1 BP) S T.
- BP_to_OBP⎽⇒ f = BP_to_OBP⎽⇒ g → f=g.
- intros; change with ( (⊩) ∘ f \sub \c = (⊩) ∘ g \sub \c);
+theorem BP_to_OBP_faithful: faithful2 ?? BP_to_OBP.
+ intros 5 (S T); change with ( (⊩) ∘ f \sub \c = (⊩) ∘ g \sub \c);