Three dogs sniffing each other.
Nothing is sniffing
3 dogs vs nothing
exists x1 x2.(a_topic(x1) & all x3.(n_other(x3) -> exists e1.(Theme(e1,x3) & Actor(e1,x2) & v_sniff(e1))) & (x1 = x2) & n_dog(x1) & card_eq_3(x1))
-exists e1 x1.(Actor(e1,x1) & v_sniff(e1) & n_thing(x1))