One eigenvalue identity unifies ridge regression, early stopping, PageRank, and Schrödinger's equation. Here's the math, the Qiskit-style walkthrough, a toy chatbot trained with kernel ridge regression — and a benchmark showing that for D ≈ 6k, PyTorch-on-CPU beats GPU. Paper + code + interactive demos.
Your Ridge Parameter Is PageRank's Damping Factor (and Why BLAS Beats GPU for Mid-Sized KRR)
