proposition: Lemma sgr_neighpr_same p x b : {in neighpr p x b &, forall y z, (sgr p.[y] = sgr p.[z])}.
proof: Proof. by rewrite /neighpl=> y z *; apply: (polyrN0_itv (@next_noroot p x b)). Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg poly polydiv ssrnum zmodp) mathcomp(polyorder path interval ssrint)