Four people watching a man standing in the river
The river is empty.
Either a man is standing in a river or the river is empty, but it can't be both
exists e1 x1 x2 x3 x4 x5.(n_river(x5) & a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_watch(e1) & in(x3,x5) & n_standing(x3) & of(x3,x4) & n_man(x4) & (x1 = x2) & n_people(x1) & card_eq_4(x1))
exists s1 x1.(n_river(x1) & Theme(s1,x1) & a_empty(s1))