Old man walking on the sidewalk.
A man is sleeping.
A man does not have to be old. People are not walking when they are sleeping.
exists e1 s1 x1 x2 x3.(n_sidewalk(x3) & a_topic(x1) & on(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_man(x1) & a_old(s1) & Theme(s1,x1))
exists e1 x1.(Actor(e1,x1) & v_sleep(e1) & n_man(x1))