proposition: Lemma intr_aut nu x : (nu x \is a int_num) = (x \is a int_num).
proof: Proof. by rewrite !intrE -rmorphN !natr_aut. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)