proposition: Lemma prod_norm_scale (l : K) (x : U * V) : `| l *: x | = `|l| * `| x |.
proof: Proof. by rewrite prod_normE /= !normrZ maxr_pMr. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrint ssrnum finmap matrix) mathcomp(rat interval zmodp vector fieldext falgebra) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality set_interval Rstruct) ereal reals signed topology prodnormedzmodule