A brown dog in a field.
The dog on the field is brown
Both sentence are talking about brown dog.
exists s1 x1 x2.(a_topic(x1) & in(x1,x2) & n_field(x2) & n_dog(x1) & a_brown(s1) & Theme(s1,x1))
exists s1 x1 x2.(n_field(x2) & n_dog(x1) & Theme(s1,x1) & a_brown(s1) & on(x1,x2))