proposition: Lemma invf_gt1 x : 0 < x -> (1 < x^-1) = (x < 1).
proof: Proof. by move=> x0; rewrite invf_pgt ?invr1 ?posrE. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)