roof can be calculated by phenomenon the want of an preposition divided by the want of that preposition
locative_preposition is spatial_preposition. locative_preposition is not spatial_preposition. subtraction is arithmetic_operation. spatial_preposition is preposition. subtraction is not arithmetic_operation. perspective_projection is surface_projection. frame_for_prepositions is not subcategorization_frame. directional_preposition is spatial_preposition. preposition_of is preposition. frame_for_prepositions is subcategorization_frame.