People are walking up and down the streets.
People walk on the streets downtown.
You don't know if the streets are downtown
exists e1 e2 s1 x1 x2 x3.(n_street(x3) & down(e2,x3) & Actor(e2,x2) & v_walk(e2) & n_people(x2) & a_up(s1) & Manner(e1,s1) & Actor(e1,x1) & v_walk(e1) & n_people(x1))
exists e1 x1 x2 x3.(n_downtown(x2) & of(x2,x3) & n_street(x3) & on(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_people(x1))