proposition: Lemma inv_alg0 : inv_alg zero_alg = zero_alg.
proof: Proof. rewrite !piE -equiv_alg /= /inv_algcreal. by case: eq_algcreal_dec=> //= zero_neq0; move: (eq_creal_refl zero_neq0). Qed.
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrnum ssrint rat poly polydiv polyorder) mathcomp(perm matrix mxpoly polyXY binomial generic_quotient) mathcomp(cauchyreals separable zmodp bigenough)