arXiv Computer Vision

Predictive Latents for Autoregressive Language Models: Possibility, Gauge, and Obstruction

The paper investigates how autoregressive language models can iterate a hidden state without emitting tokens, identifying three distinct risks associated with a latent process: token risk, teacher‑forced latent risk, and open‑loop risk. It shows that when the Bayes next‑token posterior depends on a full‑rank $k$‑dimensional statistic, a width‑$k$ latent with linear least‑squares transition and a refitted unembedding can match the Bayes token predictor, but this match is only up to an invertible gauge. The study also highlights sharp obstructions: a constant latent can drive teacher‑forced risk to zero while token cross‑entropy reverts to marginal entropy, and a perfect token predictor may still conceal a null‑space walk that causes open‑loop error to grow linearly with horizon, indicating that small latent or token losses alone do not guarantee accurate latent rollout without additional rank or injectivity conditions.

arXiv AI
Oct 16

Learning to Read Out: Unembedding Dynamics in Language Model Pretraining

The paper investigates when a language model actually learns task information versus when its readout (unembedding matrix) learns to express that information. Using a new parameter‑trajectory cross‑coding method, the authors find that hidden states can encode task data early in training, but the readout reorganizes only in a narrow window (0.4–1.1% of Pythia’s pretraining). By varying the readout learning rate, they show that faster readout learning reduces the gap between hidden‑state encoding and output expression without affecting final performance.

By Matteo He, William F. Shen, Alex Iacob, Andrej Jovanovic, Xinchi Qiu, Nicholas D. Lane
arXiv Machine Learning
Sep 23

What Does Chain-of-Thought Entropy Measure? A Channel Audit of Scaffolding, Routing, and Content

The paper investigates how entropy over chain‑of‑thought tokens influences policy decisions such as gradient application, pruning, and collapse detection. By separating scaffold tokens from substantive content, the authors analyze entropy, Kullback–Leibler divergence, and entropy velocity for each channel, proving differences between raw and content conventions and bounding answer diversity. Empirical results across 23 configurations show that scaffold tokens can account for up to 41% of high‑entropy positions, with entropy share growing through distillation, while content conventions outperform raw surprisal on compression tasks and reveal significant answer leakage in re‑fed chains.

By Marios Papamichalis, Regina Ruane
arXiv AI
Aug 7

DASH: Divergence-Adaptive Supervision Horizons for On-Policy Self-Distillation of Reasoning Models

arXiv:2608. 06243v1 Announce Type: new Abstract: Reinforcement learning with verifiable rewards (RLVR) improves the reasoning capabilities of large language models using automatically verifiable outcome signals, but these signals are typically sparse and at the sequence-level.

By ZhiYan Hou, Xinyu Tang, Hongyan An, Jianjin Zhang, Weizhen Wang, Yunyun Han, Gengsheng Li, Xiangzhao Hao, Haiyun Guo, Wenbin Hu, Jinqiao Wang, Yafeng Deng