proposition: Lemma sqrtr_gt0 a : (0 < sqrt a) = (0 < a).
proof: Proof. by rewrite lt0r sqrtr_ge0 sqrtr_eq0 -ltNge andbT. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)