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

theorem Th8:
  G={A,B,C,D} & A<>B & B<>C & B<>D implies CompF(B,G) = A '/\' C '/\' D
proof
  {A,B,C,D} = {B,A,C,D} by ENUMSET1:65;
  hence thesis by Th7;
end;
