occupies spatial region at some time has spatial occupant at some time part of continuant at some time has continuant part at some time part of continuant at all times that whole exists has continuant part at all times that part exists spatial region true true (forall (x) (if (SpatialRegion x) (Continuant x))) // axiom label in BFO2 CLIF: [035-001] s-region SpatialRegion (forall (x y t) (if (and (SpatialRegion x) (continuantPartOfAt y x t)) (SpatialRegion y))) // axiom label in BFO2 CLIF: [036-001] A spatial region is a continuant entity that is a continuant_part_of spaceR as defined relative to some frame R. (axiom label in BFO2 Reference: [035-001]) All continuant parts of spatial regions are spatial regions. (axiom label in BFO2 Reference: [036-001]) BFO 2 Reference: Spatial regions do not participate in processes. Spatial region doesn't have a closure axiom because the subclasses don't exhaust all possibilites. An example would be the union of a spatial point and a spatial line that doesn't overlap the point, or two spatial lines that intersect at a single point. In both cases the resultant spatial region is neither 0-dimensional, 1-dimensional, 2-dimensional, or 3-dimensional. immaterial entity