A guy skateboarding on the side of steps.
The skater is an athlete.
Being a skater doesn't imply being an athlete
exists e1 x1 x2 x3 x4.(n_side(x3) & a_topic(x1) & on(e1,x3) & of(x3,x4) & n_step(x4) & Actor(e1,x2) & v_skateboard(e1) & (x1 = x2) & n_guy(x1))
exists p1 x1.(n_skater(x1) & exists x2.((x1 = x2) & n_athlete(x2)))