proposition: Lemma from_algK : cancel from_alg (to_alg _).
proof: Proof. move=> x; unlock from_alg; rewrite -{2}[x]reprK piE -equiv_alg /= cst_pi. by apply: eq_to_alg_creal; rewrite from_alg_crealK to_alg_creal_repr. 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)