fact: Definition Rnat_E := (Rnat_eqE, Rnat_ltE, Rnat_leE).
imports: ZArith Lia mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq zmodp) mathcomp(path choice fintype tuple finset ssralg ssrnum bigop ssrint) CoqEAL(hrel param refinements pos)