fact: Record pos := pos_of { val_of_pos : nat; _ : (val_of_pos > 0)%N }.
imports: HB(structures) ZArith mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq zmodp) mathcomp(path choice fintype tuple finset ssralg ssrnum bigop ssrint) CoqEAL(hrel param refinements)