A woman is holding a child.
Nobody is here.
If a woman is holding a child, then someone is here.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_hold(e1) & n_child(x2) & n_woman(x1))
-exists s1 x1.(Theme(s1,x1) & a_here(s1) & n_person(x1))