Accurate and Diverse LLM Mathematical Reasoning via Automated PRM-Guided GFlowNets

Achieving both accuracy and diverse reasoning remains challenging for Large Language Models (LLMs) in complex domains like mathematics. A key bottleneck is evaluating intermediate reasoning steps to guide generation without costly human annotations. To address this, we first introduce a novel Process Reward Model (PRM) trained automatically using Monte Carlo Tree Search coupled with a similarity-based data augmentation technique, effectively capturing step-level reasoning quality. Leveraging this PRM, we then adapt Generative Flow Networks (GFlowNets) to operate at the reasoning step level. Unlike traditional reinforcement learning focused on maximizing a single reward, GFlowNets naturally sample diverse, high-quality solutions proportional to their rewards, as measured by our PRM. Empirical evaluation shows strong improvements in both accuracy and solution diversity on challenging mathematical benchmarks (e.g., +2.59% absolute accuracy on MATH Level 5 for Llama3.2-3B), with effective generalization to unseen datasets (+9.4% absolute on SAT MATH). Our work demonstrates the potential of PRM-guided, step-level GFlowNets for developing more robust and versatile mathematical reasoning in LLMs.

@article{younsi2025_2504.19981,
  title={ Accurate and Diverse LLM Mathematical Reasoning via Automated PRM-Guided GFlowNets },
  author={ Adam Younsi and Abdalgader Abubaker and Mohamed El Amine Seddik and Hakim Hacid and Salem Lahlou },
  journal={arXiv preprint arXiv:2504.19981},
  year={ 2025 }
}