proposition: Lemma distn_eq0 n1 n2 : (`|n1 - n2| == 0) = (n1 == n2).
proof: Proof. by rewrite absz_eq0 subr_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)