proposition: Lemma neq0 x : unify_nz !=0 nz -> x%:num != x0 :> T.
proof: Proof. by case: x => [x /= /andP[]]; move: cond nz => [[[]|]|] []. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(mathcomp_extra)