The relevant paper: "A Theory of Generalization in Deep Learning". https://arxiv.org/abs/2605.01172

I interpreted the kernel K of this paper as the BRDF in Rendering Equation[0] and its familiar diffusion process (from light transport simulation, or really any integro-differential equation system); together with https://en.wikipedia.org/wiki/Neural_tangent_kernel I hope this paper might be accessible with some study

[0] https://en.wikipedia.org/wiki/Rendering_equation