reserve i,j for Nat;
reserve A,B for Ring;
reserve K, L for Field;

theorem Th49:
  for x be Element of F_Complex, z, w be Element of FQ(x) holds
  (FQ_add(x)).(z,w) = z+w
  proof
    let x be Element of F_Complex;
    let z, w be Element of FQ(x);
    thus (FQ_add(x)).(z,w) = addcomplex.(z,w) by FUNCT_1:49,ZFMISC_1:87
    .= z+w by BINOP_2:def 3;
  end;
