proposition: Lemma expf_neq0 x m : x != 0 -> x ^+ m != 0.
proof: Proof. by move=> x_nz; rewrite expf_eq0; apply/nandP; right. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)