∀ {S : Type u_2} {m : Type u_5} [inst : CommRing S] (M M_1 : Matrix m m S),
  M = M_1 →
    ∀ {inst_1 : DecidableEq m} [inst_2 : DecidableEq m] (k k_1 : m),
      k = k_1 →
        ∀ (a a_1 : m),
          a = a_1 →
            ∀ (a_2 a_3 : m),
              a_2 = a_3 →
                Algebra.Norm.Transitivity.cornerAddX M k a a_2 = Algebra.Norm.Transitivity.cornerAddX M_1 k_1 a_1 a_3