reserve Y for non empty set,
  a, b for Function of Y,BOOLEAN,
  G for Subset of PARTITIONS(Y),
  A, B for a_partition of Y;

theorem
  G is independent implies Ex(All('not' a,A,G),B,G) '<' 'not' Ex(All(a,B
  ,G),A,G)
proof
A1: 'not' All(Ex(a,A,G),B,G) = Ex(All('not' a,A,G),B,G) by Th19;
  assume G is independent;
  hence thesis by A1,PARTIT_2:11,17;
end;
