fact: Definition natrE x : (x \is a nat_num) = ((trunc x)%:R == x) := @ssrnum.Num.Theory.mc_2_0.natrE R x.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)