reserve Y for non empty set,
  G for Subset of PARTITIONS(Y),
  A,B,C,D,E,F for a_partition of Y;

theorem
  G={A,B,C} & B<>C & C<>A implies CompF(C,G) = A '/\' B
proof
  {A,B,C} = {C,A,B} by ENUMSET1:59;
  hence thesis by Th4;
end;
