proposition: Lemma Ymon_bij : bijective Ymon.
proof: Proof. by exists monsY; [exact: YmonK | exact: monsYK]. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssrint rat ssralg ssrnum algC matrix vector) mathcomp(mpoly) tools partition ordtype antisym Schur_mpoly Schur_altdef sympoly homogsym permcent