fact: Definition ltez_natE := (ltez_nat, lteNz_nat, ltezN_nat, le0z_nat, lez0_nat).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)