reserve w, w1, w2 for Element of ExtREAL;
reserve c, c1, c2 for Complex;
reserve A, B, C, D for complex-membered set;
reserve F, G, H, I for ext-real-membered set;
reserve a, b, s, t, z for Complex;
reserve f, g, h, i, j for ExtReal;
reserve r for Real;
reserve e for set;

theorem Th35:
  (A \+\ B)"" = (A"") \+\ (B"")
proof
  thus (A \+\ B)"" = ((A\B)"") \/ ((B\A)"") by Th32
    .= ((A"")\(B"")) \/ ((B\A)"") by Th34
    .= (A"") \+\ (B"") by Th34;
end;
