Young hockey players play on rollerskates.
People play in roller skates.
Young hockey players are a form of people.
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_rollerskate(x3) & Actor(e1,x1) & v_play(e1) & n_player(x1) & of(x1,x2) & n_hockey(x2) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(in(e1,x2) & n_skate(x2) & of(x2,x3) & n_roller(x3) & Actor(e1,x1) & v_play(e1) & n_people(x1))