proposition: Lemma join_Young_le sh1 sh2 : (sh1 <= join_Young sh1 sh2)%O.
proof: Proof. by apply/le_YoungP => i; rewrite nth_join_Young leq_maxl. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass sorted ordtype