proposition: Fact trivsetpart_top P : (P <= trivsetpart S)%O.
proof: Proof. apply/is_finer_pblockP=> x xinS. apply/subsetP=> y; rewrite pblock_trivsetpart //. move: xinS; rewrite -{1}(cover_setpart P). by move/pblock_mem/setpart_subset/subsetP; apply. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass sorted ordtype partition