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,D} & A<>D & B<>D & C<>D implies CompF(D,G) = A '/\' C '/\' B
proof
  {A,B,C,D} = {D,A,C,B} by ENUMSET1:70;
  hence thesis by Th7;
end;
