proposition: Lemma norm_algN x : norm_alg (- x) = norm_alg x.
proof: Proof. rewrite -[x]reprK !piE /= -equiv_alg !norm_algcrealE; apply: eq_crealP. exists_big_modulus m F=> [e i e_gt0 hi /=|]. by rewrite normrN subrr normr0. by close. 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)