Revisiting LLM Reasoning via Information Bottleneck

Fuente: arXiv
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Main Authors: Lei, Shiye, Cheng, Zhihao, Jia, Kai, Tao, Dacheng
Format: Preprint
Published: 2025
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author Lei, Shiye
Cheng, Zhihao
Jia, Kai
Tao, Dacheng
author_facet Lei, Shiye
Cheng, Zhihao
Jia, Kai
Tao, Dacheng
contents Large language models (LLMs) have recently demonstrated remarkable progress in reasoning capabilities through reinforcement learning with verifiable rewards (RLVR). By leveraging simple rule-based rewards, RL effectively incentivizes LLMs to produce extended chain-of-thought (CoT) reasoning trajectories, progressively guiding them toward correct answers. However, existing approaches remain largely heuristic and intuition-driven, limiting the development of principled methodologies. In this paper, we present a theoretical characterization of LLM reasoning grounded in information bottleneck (IB) principle, introducing IB-aware reasoning optimization (IBRO), a framework that encourages reasoning trajectories to be both informative about the final correct answer and generalizable across diverse prompts. We derive a practical token-level surrogate objective and propose an efficient approximation, resulting in the lightweight IB regularization method. This technique integrates seamlessly into existing RL-based post-training frameworks without additional computational overhead, requiring only a one-line code modification. Empirically, we validate IB regularization across multiple mathematical reasoning benchmarks and RL algorithms, demonstrating consistent improvements in LLM reasoning performance.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18391
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Revisiting LLM Reasoning via Information Bottleneck
Lei, Shiye
Cheng, Zhihao
Jia, Kai
Tao, Dacheng
Artificial Intelligence
Large language models (LLMs) have recently demonstrated remarkable progress in reasoning capabilities through reinforcement learning with verifiable rewards (RLVR). By leveraging simple rule-based rewards, RL effectively incentivizes LLMs to produce extended chain-of-thought (CoT) reasoning trajectories, progressively guiding them toward correct answers. However, existing approaches remain largely heuristic and intuition-driven, limiting the development of principled methodologies. In this paper, we present a theoretical characterization of LLM reasoning grounded in information bottleneck (IB) principle, introducing IB-aware reasoning optimization (IBRO), a framework that encourages reasoning trajectories to be both informative about the final correct answer and generalizable across diverse prompts. We derive a practical token-level surrogate objective and propose an efficient approximation, resulting in the lightweight IB regularization method. This technique integrates seamlessly into existing RL-based post-training frameworks without additional computational overhead, requiring only a one-line code modification. Empirically, we validate IB regularization across multiple mathematical reasoning benchmarks and RL algorithms, demonstrating consistent improvements in LLM reasoning performance.
title Revisiting LLM Reasoning via Information Bottleneck
topic Artificial Intelligence
url https://arxiv.org/abs/2507.18391