The intersection of a 4D line segment and a 3D polyhedron in 4D is indeed a point if they intersect, assuming they are not confined to the same 3D space. This conclusion aligns with the concept that a line in a higher dimension can intersect a lower-dimensional object at a single point. To prove this, one can analyze the situation using a coordinate system that aligns the 3D polyhedron with the axes. The reasoning parallels that of a line intersecting a plane in 3D, extended to an additional dimension. Thus, the intersection remains a singular point in 4D space.