proposition: Lemma has_algidP {U} : reflect (exists e, is_algid e U) (has_algid U).
proof: Proof. exact: sumboolP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype div tuple finfun bigop ssralg) mathcomp(finalg zmodp matrix vector poly)