A man with his young children.
The man doesn't know the kids.
A man who is with his young children will definitely know the kids.
exists s1 x1 x2.(a_topic(x1) & with(x1,x2) & n_child(x2) & a_young(s1) & Theme(s1,x2) & of(x2,x1) & n_male(x1) & n_man(x1))
exists x1 x2.(n_kid(x2) & n_man(x1) & -exists e1.(Theme(e1,x2) & Actor(e1,x1) & v_know(e1)))