proposition: Lemma intr_int m : m%:~R \is a int_num.
proof: Proof. by rewrite intrE; case: m => n; rewrite ?opprK natr_nat ?orbT. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)