People are on a ledge outside of a building.
People are sitting in a library.
On and sitting are not the same. Outside and in are different locations. Building and library may not be the same.
exists p1 x1.(exists x2 x3 x4.(on(x1,x2) & of(x3,x4) & n_building(x4) & outside(x2,x3) & n_thing(x3) & n_ledge(x2)) & n_people(x1))
exists e1 x1 x2.(in(e1,x2) & n_library(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1))