proposition: Lemma cone_composable_fiprod_cone : forall a u v y1 y2 z, fiprod_hypothesis a u v y1 y2 -> mor a z -> source y1 = target z -> cone_composable (fiprod_cone a u v y1 y2) z.
proof: Proof. ir. uhg; ee. app is_cone_fiprod_cone. rww cone_target_fiprod_cone. rww vertex_fiprod_cone. sy; am. Qed.
imports: Arith colimits little_cat fc_limits cardinal