Strict Total Positivity from Spectral Darboux and Toeplitz Smoothing Mechanisms
arXiv:2607.02778
2026
Architecture
1 ideas extracted · analyzed Aug 30, 2026
What the math gives to ML
The paper isolates strict total positivity as a mechanism for turning ordered one-dimensional families into matrices whose every ordered minor is positive, with the modified-Bessel kernel I_s(x) as a concrete infinite-order example. This structure is transferable to sequence models because attention and convolution operators are ordered kernel matrices, and positive minors impose an anti-oscillatory or variation-diminishing bias beyond entrywise positivity. The most direct experiment is a content-light attention layer whose weights are generated by the Bessel kernel on positive ordered scalar coordinates, followed by row normalization. A cheaper variant can regularize only low-order minors of an ordinary learned attention matrix.
Ideas from this paper
Unverified
2026
Replace ordinary dot-product attention logits with a strictly totally positive kernel evaluated on positive, ordered scalar coordinates attached to queries and keys. Use the modified-Bessel kernel K(x,s)=I_s(x), whose every ordered minor is positive, then row-normalize it as an attention matrix. This creates an attention operator with a mathematically enforced anti-oscillatory structure rather than merely positive entries.
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