Assertion: sphere | /r/CapableOf | lack boundary
Facets:
value: with constant, positive gaussian curvature
type: OTHER
Source sentences:
text: All these other surfaces would have boundaries, and the sphere is the only surface that lacks a boundary with constant, positive Gaussian curvature.
text: The sphere is the only imbedded surface that lacks boundary or singularities with constant positive mean curvature.