proposition: Lemma wordering_cle_pr x: cardinal_set x -> (worder_on (graph_on cardinal_le x) x).
proof: Proof. move=> alc; apply: (wordering_pr cle_wor). move=> a ax; move: (alc _ ax); fprops. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)