proposition: Lemma sgr_denq x : sgr (denq x) = 1.
proof: Proof. by apply/eqP; rewrite sgr_cp0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)