proposition: Lemma invf_ge1 x : 0 < x -> (1 <= x^-1) = (x <= 1).
proof: Proof. by move=> x0; rewrite invf_pge ?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)