Research ideas

Local Irreducible-Vertex Preconditioner

Use the paper’s observation that the fully irreducible vertex is approximately local after crossed-channel ladders are removed to build a block-local curvature correction for neural-network optimization. Estimate a cheap bare covariance and subtract the inverse full covariance to obtain a local irreducible correction, avoiding a dense four-point model while retaining interaction effects that ordinary diagonal preconditioners miss.