The Spherical Grünbaum Inequality
arXiv:2607.16924
2026
Regularization
1 ideas extracted · analyzed Aug 30, 2026
What the math gives to ML
The paper gives a sharp, dimension-dependent lower bound on how much spherical convex mass must lie on either side of every hyperplane through the spherical centroid. The transferable asset is a geometric anti-collapse certificate: a nondegenerate set on a hypersphere cannot place less than approximately e^{-1} of its mass in any centroid-tangent hemisphere. This can be converted into a regularizer for hyperspherical embeddings, prototypes, or latent codes that penalizes directional imbalance without choosing fixed coordinate axes. The theorem applies exactly to uniform measure on a spherical convex body, while neural implementations should treat its empirical soft version as a heuristic or diagnostic for arbitrary point clouds.
Ideas from this paper
Unverified
2026
Add a coordinate-free regularizer that prevents a batch of unit-normalized embeddings from concentrating almost entirely on one side of a hyperplane passing through their spherical centroid. Sample random directions tangent to the estimated centroid, measure the soft fraction of embeddings in each corresponding hemisphere, and penalize fractions below the spherical Grünbaum constant. This targets directional mode collapse while preserving rotational invariance.
Useful5/10
Difficulty3/10
Novelty7/10