Linked from

The 40 pages that link to Sphere, each with the reason it gives.

• CircleCompared with: It extends the circle’s equal-distance definition from a plane into space.

• TorusCompared with: Unlike the torus, every loop on a sphere contracts to a point.

• Oblate spheroidCompared with: A sphere has no polar flattening or equatorial bulge.

• ConeCompared with: A sphere has no base or apex, unlike a cone’s pointed, one-sided form.

• Figure of the EarthCompared with: A sphere is simpler than Earth’s figure but ignores polar flattening.

• Flat torusCompared with: A sphere cannot carry a smooth metric of zero curvature everywhere while retaining its usual topology.

• Cartan–Hadamard theoremCompared with: Positive curvature and multiple geodesics prevent the theorem's global exponential-map conclusion.

• Earth ellipsoidCompared with: A sphere ignores polar flattening that Earth ellipsoids explicitly model.