One biker wearing a helmet is jumping over an obstacle.
One biker wearing no helmet is jumping over an obstacle.
The biker can't have a helmet and no helmet on at the same time.
exists e1 e2 s1 x1 x2 x3 x4.(a_over(s1) & Manner(e2,s1) & Theme(e2,x4) & Actor(e2,x1) & v_jump(e2) & n_obstacle(x4) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_helmet(x3) & (x1 = x2) & n_biker(x1) & card_eq_1(x1))
exists e1 s1 x1 x2 x3.(a_over(s1) & Manner(e1,s1) & Theme(e1,x3) & Actor(e1,x1) & v_jump(e1) & n_obstacle(x3) & -exists e2 x4.(Theme(e2,x4) & Actor(e2,x2) & v_wear(e2) & n_helmet(x4)) & (x1 = x2) & n_biker(x1) & card_eq_1(x1))