A small white dog running on a pebble covered beach.
A dog runs after his boy and the frisbee.
A dog could be running on a beach for many reasons. Running after a boy and frisbee add a lot more context and can't be inferred just from knowing that the dog is running. "Running after" is more specific than "running".
exists e1 s1 s2 s3 s4 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_beach(x3) & a_covered(s4) & Theme(s4,x3) & a_pebble(s3) & Theme(s3,x3) & Actor(e1,x2) & v_run(e1) & (x1 = x2) & n_dog(x1) & a_white(s2) & Theme(s2,x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2 x3 x4.(n_frisbee(x4) & after(e1,x2) & subset_of(x4,x2) & subset_of(x3,x2) & n_boy(x3) & of(x3,x1) & n_male(x1) & Actor(e1,x1) & v_run(e1) & n_dog(x1))