A security guard on watch duty at the museum.
The museum has no security personnel.
IF A SECURITY GUARD IS ON WATCH THEN NO SECURITY IS FALSE
exists x1 x2 x3 x4 x5.(n_museum(x5) & a_topic(x1) & on(x1,x3) & at(x3,x5) & n_duty(x3) & of(x3,x4) & n_watch(x4) & n_guard(x1) & of(x1,x2) & n_security(x2))
exists x1.(n_museum(x1) & -exists e1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_personnel(x2) & of(x2,x3) & n_security(x3)))