proposition: Lemma ratzE n : ratz n = n%:Q.
proof: Proof. elim: n=> [|n ihn|n ihn]; first by rewrite mulr0z ratz_frac. by rewrite intS mulrzDr_tmp ratzD ihn. by rewrite intS opprD mulrzDr_tmp ratzD ihn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)