b occurs_in c =def b is a process and c is a material entity or immaterial entity& there exists a spatiotemporal region r and b occupies_spatiotemporal_region r.& forall(t) if b exists_at t then c exists_at t & there exist spatial regions s and s’ where & b spatially_projects_onto s at t& c is occupies_spatial_region s’ at t& s is a proper_continuant_part_of s’ at t