A classroom includes students who observe their professor lecture on the marker board.
There are no students in the classroom.
A classroom cannot include students while there are no students in there.
exists e2 e1 x1 x2 x3 x4 x5 x6 x7.(n_board(x6) & of(x6,x7) & n_marker(x7) & Theme(e2,x2) & Actor(e2,x1) & v_include(e2) & Theme(e1,x4) & Actor(e1,x3) & v_observe(e1) & on(x4,x6) & n_lecture(x4) & of(x4,x5) & n_professor(x5) & of(x4,x1) & n_thing(x1) & (x2 = x3) & n_student(x2) & n_classroom(x1))
exists p1 x1 x3.(n_classroom(x3) & -exists x2.((x1 = x2) & in(x2,x3) & n_student(x2)))