The surfer in the wetsuit is riding a wave.
The surfer in the wetsuit is riding a horse.
One cannot be riding a wave and riding a horse simultaneously.
exists e1 x1 x2 x3.(n_wetsuit(x2) & n_surfer(x1) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_wave(x3) & in(x1,x2))
exists e1 x1 x2 x3.(n_wetsuit(x2) & n_surfer(x1) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_horse(x3) & in(x1,x2))