Three swimmers are swimming or racing in separate lanes.
Nothing is swimming
Three swimmers can not be swimming if nothing is swimming.
(exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_swim(e1) & n_lane(x2) & a_separate(s1) & Theme(s1,x2) & n_swimmer(x1) & card_eq_3(x1)) | exists e2 s2 x3 x4.(in(e2,x4) & n_lane(x4) & a_separate(s2) & Theme(s2,x4) & Actor(e2,x3) & v_race(e2) & n_swimmer(x3) & card_eq_3(x3)))
-exists e1 x1.(Actor(e1,x1) & v_swim(e1) & n_thing(x1))