Bianchi–Gruber conjecture on centrally symmetric sections
Bianchi–Gruber conjecture on centrally symmetric sections
Let , , be a strictly convex body, and let be a family of hyperplanes that is the image of an embedding of the tangent bundle of the sphere , with every hyperplane in intersecting the interior of . Bianchi–Gruber conjecture. If every such intersection is centrally symmetric and, with possibly a few exceptions, does not contain a possibly existing center of symmetry of , then is an ellipsoid. The conjecture is known under the stronger assumption that all the sections are ellipsoids, while the stated version remains open.
Sources & referencesView supporting material
Primary source
Bartłomiej Zawalski, “On flat shadow boundaries from point light sources and the characterization of ellipsoids”, arXiv:2603.29130 (2026).
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