a boy in green shorts swims past a boy in black shorts in an outdoor pool.
Nobody is swimming.
A boy swims so it is not true that nobody is swimming.
exists e1 s1 s2 s3 x1 x2 x3 x4 x5.(past(e1,x3) & in(x3,x4) & in(x4,x5) & n_pool(x5) & a_outdoor(s3) & Theme(s3,x5) & n_shorts(x4) & a_black(s2) & Theme(s2,x4) & n_boy(x3) & Actor(e1,x1) & v_swim(e1) & in(x1,x2) & n_shorts(x2) & a_green(s1) & Theme(s1,x2) & n_boy(x1))
-exists p1 x1.(exists x2.((x1 = x2) & n_swimming(x2)) & n_person(x1))