A woman is sitting in the train.
The woman is swimming.
One cannot be sitting in the train and swimming at the same time.
exists e1 x1 x2.(n_train(x2) & in(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_woman(x1))
exists p1 x1.(n_woman(x1) & exists x2.((x1 = x2) & n_swimming(x2)))