People are rollerskating in a roller rink.
People are wearing rollerskates.
Wearing rollerskates indicates they are rollerskating.
exists e1 x1 x2 x3.(in(e1,x2) & n_rink(x2) & of(x2,x3) & n_roller(x3) & Actor(e1,x1) & v_rollerskate(e1) & n_people(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_rollerskate(x2) & n_people(x1))