proposition: Lemma edge_nt_fiprod_cone : forall a u v y1 y2, edge_nt (fiprod_cone a u v y1 y2) = (vee_nt a (id a (source y1)) (id a (source y2)) u v y1 (comp a u y1) y2).
proof: Proof. ir. uf fiprod_cone. rw edge_nt_cone_create. tv. Qed.
imports: Arith colimits little_cat fc_limits cardinal