A group of people are walking in a canyon.
A group of people are walking on a mountain trail
People cannot be in a canyon and in a mountain trail at the same time.
exists e1 x1 x2 x3.(in(e1,x3) & n_canyon(x3) & Actor(e1,x1) & v_walk(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3 x4.(on(e1,x3) & n_trail(x3) & of(x3,x4) & n_mountain(x4) & Actor(e1,x1) & v_walk(e1) & of(x1,x2) & n_people(x2) & n_group(x1))