proposition: Lemma fsubset_leq_card A B : A `<=` B -> (#|` A| <= #|` B|)%N.
proof: Proof. by move=> /fsubset_leqif_cards ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop)