theorem BFO.ThreeDimensionalSpatialRegion.At.toParent
theorem BFO.ThreeDimensionalSpatialRegion.At.toParent: ∀ (x t : Type) [At x t], SpatialRegion.At x t
theorem BFO.ThreeDimensionalSpatialRegion.At.toParent
theorem BFO.ThreeDimensionalSpatialRegion.At.toParent: ∀ (x t : Type) [At x t], SpatialRegion.At x t