proposition: Lemma rootC_le0 n x : (1 < n)%N -> (n.-root x <= 0) = (x == 0).
proof: Proof. by move=> n_gt1; rewrite le_eqVlt rootC_lt0 // orbF rootC_eq0 1?ltnW. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)