proposition: Lemma natr_normK x : x \is a nat_num -> `|x| ^+ 2 = x ^+ 2.
proof: Proof. by move/Rreal_nat/real_normK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)