A girl rides a unicycle with a child who rides a scooter.
Nobody is riding
If the girl rides a unicycle then it's impossible that nobody is riding.
exists e2 e1 x1 x2 x3 x4 x5.(with(e1,x3) & Theme(e2,x5) & Actor(e2,x4) & v_ride(e2) & n_scooter(x5) & (x3 = x4) & n_child(x3) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_unicycle(x2) & n_girl(x1))
-exists e1 x1.(Actor(e1,x1) & v_ride(e1) & n_person(x1))