proposition: Lemma mx_normrE (K : realDomainType) (m n : nat) (x : 'M[K]_(m, n)) : mx_norm x = \big[maxr/0]_ij `|x ij.1 ij.2|.
proof: Proof. rewrite /mx_norm; apply/esym. elim/big_ind2 : _ => //= a a' b b' ->{a'} ->{b'}. by have [ab|ab] := leP a b; [rewrite max_r | rewrite max_l // ltW]. 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