proposition: Lemma msetn_inj n : n > 0 -> injective (@msetn K n).
proof: Proof. move=> n_gt0 a b eqsab; apply/(gt0_msetnP _ _ n_gt0). by rewrite -eqsab inE n_gt0 eqxx. Qed.
imports: mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop tuple) finmap