fact: Definition nat_of_N_expand (n : N) : nat := if n is N.pos p then nat_of_pos_expand p else 0%N.
imports: elpi(elpi) Coq(QArith) Coq.micromega(OrderedRing RingMicromega) mathcomp(all_ssreflect ssralg ssrnum ssrint) mathcomp.zify(ssrZ zify)