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Inscribed Polytope


An inscribed polytope is a convex polytope whose vertices all lie on a common hypersphere. Fixing the hypersphere removes the freedom to enlarge the polytope by dilation. One extremal question asks for the largest content at a prescribed number of vertices.

For vertices on the unit hypersphere S^3, Medgyes (2026) proved that the maximum content with seven vertices is sqrt(3)/4. No maximizer is a cyclic polytope. With eight vertices, the maximum is 2/3, attained uniquely, up to orthogonal transformations, by the regular 16-cell. The proof uses certificates from sum-of-squares optimization checked in exact arithmetic. Medgyes (2026) reports AI assistance with mathematical discussions and implementation of the computations.


See also

Convex Polytope, Cyclic Polytope, Hypersphere

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References

Medgyes, C. "Inscribed 4-Polytopes of Maximal Volume with Seven and Eight Vertices." 12 Oct 2026. https://arxiv.org/abs/2610.26886.

Cite this as:

Weisstein, Eric W. "Inscribed Polytope." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/InscribedPolytope.html

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