proposition: Fact invq_frac x : x.1 != 0 -> x.2 != 0 -> invq (fracq x) = fracq (invq_subdef x).
proof: Proof. by rewrite invq_def; case: (fracqP x) => // k ? k0; rewrite fracqMM. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)