proposition: Lemma exprn_even_ge0 n x : ~~ odd n -> 0 <= x ^+ n.
proof: Proof. by move=> even_n; rewrite real_exprn_even_ge0 ?num_real. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)