Optimal mean width and metric entropy estimates for convex bodies

arXiv:2607.29522 2026 Geometry 1 ideas extracted · analyzed Aug 31, 2026

What the math gives to ML

The paper establishes an affine-normalization principle: every convex body admits a linear image whose Euclidean covering entropy is controlled, up to universal constants, by that of the crosspolytope, while the optimal mean-width-to-volume-radius ratio is at most O(sqrt(log(en))). The transferable asset is the use of determinant-constrained linear transformations to remove harmful anisotropy without allowing representation collapse, together with mean width and covering entropy as geometric compactness criteria. A practical neural-network adaptation is to insert a learned determinant-one affine preconditioner on hidden representations and optimize a sampled mean-width-to-volume proxy, testing whether it produces more compressible and better-conditioned activations than LayerNorm or whitening.

Ideas from this paper

Unverified 2026

Affine mean-width normalization

Replace or augment LayerNorm on a hidden representation by a learned volume-preserving linear map that minimizes the representation cloud's spherical mean width relative to a volume proxy. The determinant constraint prevents trivial shrinking, so the module targets anisotropy and elongated activation clouds; the expected benefit is a tighter geometry that is easier to quantize or cover with a small codebook.

Useful5/10
Difficulty6/10
Novelty7/10
Paper: Optimal mean width and metric entropy estimates for convex bodies arXiv:2607.29522