arXiv Computation and Language

LLMs Think with DAGs: Probing the Latent Graph Structure of Reasoning

The paper introduces Reasoning DAG Probing, a method that treats premises, intermediate conclusions, and final answers as nodes in a directed acyclic graph (DAG). By training lightweight probes on LLM hidden states, the authors show that DAG structure is encoded in the models, peaking in intermediate layers and becoming stronger with larger models. During autoregressive generation, the latent DAG structure emerges progressively, anticipating answer correctness and enabling correction of some incorrect outputs by steering activations toward the ground‑truth DAG.

arXiv AI
Sep 10

A*-Thought-V2: Efficient Latent Reasoning via Geometric Dynamics of LLM

A*-Thought-V2 is a framework that models Chain-of-Thought reasoning as a geometric trajectory in a 3D PCA space, using explicit-implicit latent tokens to compress steps that deviate from the main question-to-solution direction. The method measures alignment angles to decide which steps remain text and which become latent, and introduces stepwise embedding forcing and label forcing to train the architecture. Experiments on Qwen models show up to 2.6% accuracy gains, halved response length, and significant reductions in computation and training time.

By Xiaoang Xu, Siyuan Liu, Shuo Wang, Junlan Feng, Fanyu Meng, Zhu Zhang, Jixun Wang, Xiaorong Wang, Zihan Zhou, Xin Li, Chaojun Xiao, Yiming Zhang, Huijia Wu, Liuyu Xiang, Peipei Li, Zhaofeng He
arXiv Machine Learning
Aug 11

Are Latent Reasoning Models Easily Interpretable?

arXiv:2604. 04902v2 Announce Type: replace Abstract: Latent reasoning models (LRMs) have attracted significant research interest due to their low inference cost (relative to explicit reasoning models) and theoretical ability to explore multiple reasoning paths in parallel.

By Connor Dilgren, Sarah Wiegreffe
arXiv Machine Learning
Oct 8

The Dichotomy Between Pattern Recognition and Step-by-Step Reasoning

The paper argues that pattern recognition and step‑by‑step reasoning lie on a spectrum, with large language models (LLMs) learning the latter when the next token depends on only a few preceding tokens. It formalises reasoning traces as paths on a De Bruijn graph, showing that the number of edges is far smaller than the number of possible traces, making step‑by‑step reasoning sample‑efficient. Experiments fine‑tuning Qwen2.5‑1.5B‑Instruct demonstrate that a moderate density of states balances accuracy and robustness, and that real‑world models like Qwen3 retain most of their performance even when attention is limited to a small sliding window.

By Amrut Nadgir, Pratik Chaudhari, Vijay Balasubramanian