Police on horseback at an outside protest.
Police are supervising the protest.
Just because the police are on horseback at an outside protest, does not imply that the police are supervising.
exists s1 x1 x2 x3.(a_topic(x1) & at(x1,x3) & n_protest(x3) & a_outside(s1) & Theme(s1,x3) & on(x1,x2) & n_horseback(x2) & n_police(x1))
exists e1 x1 x2.(n_protest(x2) & Theme(e1,x2) & Actor(e1,x1) & v_supervise(e1) & n_police(x1))