The checkpoint is not the policy: a merged reading of PDM and RLT
2026-09-13
A merged reading of two 2026 project reports from the same author line, Prefill–Decode Kernel Mismatch (an execution-level diagnosis of why same-weight sampler and trainer paths define different policies, plus contracts, audits, and four remedies) and Recurrent Looped Transformer (an architecture that designs the sampler-trainer mismatch away with one history-dependent transition): what each actually solves, what is actually measured, and the end-to-end causal loop neither has closed yet.
execution-fidelityrl-scalingimportance-samplingrecurrent-architecturenumerical-precisionaudit-discipline