People stroll outdoors at the airport.
No one is outside the airport.
There is either people or no one.
exists e1 x1 x2 x3.(n_airport(x3) & at(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_stroll(e1) & n_outdoors(x2) & n_people(x1))
exists x2.(n_airport(x2) & -exists p1 x1.(outside(x1,x2) & n_one(x1)))