The set of points in three-dimensional space.
(=> (And (Member ?X1 3d-Length-Space) (Member ?X2 3d-Length-Space))
(Quantity.Dimension (Distance ?X1 ?X2) Length-Dimension))
(=> (And (Member ?X1 3d-Length-Space) (Member ?X2 3d-Length-Space))
(Quantity.Dimension (Distance ?X1 ?X2) Length-Dimension))
(<= (Point-In $X 3d-Length-Space) (3d-Point $X))
(Inherited-Slot-Value 3d-Point Point-In 3d-Length-Space)
(<=> (3d-Point ?Pt) (Point-In ?Pt 3d-Length-Space))