three people sit in a cave.
Three people are outdoors
A cave is outdoors, so if three people are in a cave, they are also outdoors.
exists e1 x1 x2.(in(e1,x2) & n_cave(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1) & card_eq_3(x1))
exists p1 x1.(exists x2.((x1 = x2) & n_outdoors(x2)) & n_people(x1) & card_eq_3(x1))