Four ferry boats are docked at a visitor's center with passengers waiting to board.
There are no passengers waiting.
On the boats, there cannot be passengers waiting and no passengers waiting.
exists e2 e1 x1 x2 x3 x4 x5 x6 x7.(at(e1,x4) & with(x4,x5) & to(e2,x7) & n_board(x7) & Actor(e2,x6) & v_wait(e2) & (x5 = x6) & n_passenger(x5) & n_center(x4) & of(x4,x3) & n_visitor(x3) & Theme(e1,x1) & v_dock(e1) & n_boat(x1) & of(x1,x2) & n_ferry(x2) & card_eq_4(x1))
exists p1 x1.-exists e1 x2 x3.((x1 = x2) & Actor(e1,x3) & v_wait(e1) & (x2 = x3) & n_passenger(x2))