proposition: Lemma leq_norm : forall a b, b != 0 -> a %| b -> norm a <= norm b.
proof: Proof. move=> a b b0; move/dvdrP => [x hx]; rewrite hx norm_mul //. by apply: contra b0; rewrite hx; move/eqP->; rewrite mul0r. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool Arith.Wf_nat) mathcomp(eqtype ssrnat div seq path) mathcomp(ssralg fintype perm tuple choice generic_quotient) mathcomp(matrix bigop zmodp mxalgebra poly) stronglydiscrete