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 Th87:
  {f}**{h,i} = {f*h,f*i}
proof
  thus {f}**{h,i} = {f}**({h}\/{i}) by ENUMSET1:1
    .= ({f}**{h}) \/ ({f}**{i}) by Th82
    .= {f*h} \/ ({f}**{i}) by Th86
    .= {f*h} \/ {f*i} by Th86
    .= {f*h,f*i} by ENUMSET1:1;
end;
