Large Language Models

Pushing the Boundaries of Natural Reasoning: Interleaved Bonus from Formal-Logic Verification

CChuxue CaoJJinluan YangHHaoran LiKKunhao PanZZijian ZhaoZZhengyu ChenYYuchen TianLLijun WuCConghui HeSSirui HanYYike Guo
Published
January 30, 2026
Authors
11

Abstract

Large Language Models (LLMs) show remarkable capabilities, yet their stochastic next-token prediction creates logical inconsistencies and reward hacking that formal symbolic systems avoid. To bridge this gap, we introduce a formal logic verification-guided framework that dynamically interleaves formal symbolic verification with the natural language generation process, providing real-time feedback to detect and rectify errors as they occur. Distinguished from previous neuro-symbolic methods limited by passive post-hoc validation, our approach actively penalizes intermediate fallacies during the reasoning chain. We operationalize this framework via a novel two-stage training pipeline that synergizes formal logic verification-guided supervised fine-tuning and policy optimization. Extensive evaluation on six benchmarks spanning mathematical, logical, and general reasoning demonstrates that our 7B and 14B models outperform state-of-the-art baselines by average margins of 10.4% and 14.2%, respectively. These results validate that formal verification can serve as a scalable mechanism to significantly push the performance boundaries of advanced LLM reasoning.

Keywords

large language modelsformal logic verificationsymbolic verificationnatural language generationreasoning chainsupervised fine-tuningpolicy optimizationmathematical reasoninglogical reasoninggeneral reasoning

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