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An Exact Equivalence for Finite Classification Models (arxiv.org)
2 points by bwbellmath on Sep 15, 2023 | hide | past | pdf | 1 comment on HN

In plain words: Any finite neural network can be rewritten exactly as a kernel method, where a fixed similarity score between examples drives its predictions. Unlike the usual trick of freezing the network at its starting weights, this rewrite matches the trained network to machine precision.

Abstract · An Exact Kernel Equivalence for Finite Classification Models

We explore the equivalence between neural networks and kernel methods by deriving the first exact representation of any finite-size parametric classification model trained with gradient descent as a kernel machine. We compare our exact representation to the well-known Neural Tangent Kernel (NTK) and discuss approximation error relative to the NTK and other non-exact path kernel formulations. We experimentally demonstrate that the kernel can be computed for realistic networks up to machine precision. We use this exact kernel to show that our theoretical contribution can provide useful insights into the predictions made by neural networks, particularly the way in which they generalize.

Brian Bell, Michael Geyer, David Glickenstein, Amanda Fernandez, Juston Moore
arXiv:2308.00824 · cs.LG · submitted Aug 1, 2023 · updated Aug 9, 2023
abstract · pdf · html · TAG-ML at ICML 2023 in Proceedings. 8 pages, 6 figures, proofs in Appendix

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We re-explore the path kernel result from Domingos and address some errors and limitations from his approach to derive an exact and practical kernel representation.