proposition: Lemma mesym1_set1 i : mesym1 [set i] = U_(i)%MM.
proof: Proof. by apply/mnmP=> j; rewrite mnmE in_set1 mnmE eq_sym. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype tuple finfun bigop finset binomial) mathcomp(order fingroup perm ssralg zmodp poly ssrint) mathcomp(matrix vector) mathcomp(bigenough) ssrcomplements freeg