proposition: Lemma twoarrow_hypothesis_opp_flip : forall a u v, Category.axioms a -> twoarrow_hypothesis (opp a) (flip u) (flip v) = twoarrow_hypothesis a u v.
proof: Proof. ir. rw twoarrow_hypothesis_opp. rw flip_flip. rw flip_flip. tv. am. Qed.
imports: Arith colimits little_cat fc_limits cardinal