HybridProver: Augmenting Theorem Proving with LLM-Driven Proof Synthesis and Refinement

arXiv:2505.15740v2 Announce Type: replace-cross Abstract: Formal methods play a crucial role in ensuring the reliability of critical systems through rigorous mathematical verification. However, their adoption remains limited due to the labor-intensive nature of manual proof construction. Recent advances in large language models (LLMs) have opened new opportunities for automated theorem proving. Two main paradigms have emerged: stepwise tactic-based generation and whole-proof synthesis. While both approaches have complementary strengths, existing work largely treats them in isolation. In this work, we propose HybridProver, a unified framework that integrates whole-proof synthesis and tactic-based generation through proof sketches as an intermediate representation. This design enables the reuse of partially correct proof structures while effectively combining high-level planning with fine-grained reasoning. We implement HybridProver in Isabelle/HOL and post-train two 7B-scale LLMs on our optimized Isabelle datasets. Experiments on the miniF2F Isabelle benchmark achieved a 73.8% success rate and improved upon the previous state of the art (61.9%), demonstrating that lightweight models, when combined with our approach, can effectively generate Isabelle/HOL proofs without relying on very large LLMs. Ablation studies further analyze the impact of dataset quality, training configurations, and sampling strategies on proof generation.

Abstract:Formal methods play a crucial role in ensuring the reliability of critical systems through rigorous mathematical verification. However, their adoption remains limited due to the labor-intensive nature of manual proof construction. Recent advances in large language models (LLMs) have opened new opportunities for automated theorem proving. Two main paradigms have emerged: stepwise tactic-based generation and whole-proof synthesis. While both approaches have complementary strengths, existing work largely treats them in isolation. In this work, we propose HybridProver, a unified framework that integrates whole-proof synthesis and tactic-based generation through proof sketches as an intermediate representation. This design enables the reuse of partially correct proof structures while effectively combining high-level planning with fine-grained reasoning. We implement HybridProver in Isabelle/HOL and post-train two 7B-scale LLMs on our optimized Isabelle datasets. Experiments on the miniF2F Isabelle benchmark achieved a 73.8% success rate and improved upon the previous state of the art (61.9%), demonstrating that lightweight models, when combined with our approach, can effectively generate Isabelle/HOL proofs without relying on very large LLMs. Ablation studies further analyze the impact of dataset quality, training configurations, and sampling strategies on proof generation.

Formal Languages and Automata Theory (cs.FL); Artificial Intelligence (cs.AI); Software Engineering (cs.SE)

arXiv:2505.15740 [cs.FL]

(or arXiv:2505.15740v2 [cs.FL] for this version)

https://doi.org/10.48550/arXiv.2505.15740 Focus to learn more arXiv-issued DOI via DataCite

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HybridProver: Augmenting Theorem Proving with LLM-Driven Proof Synthesis and Refinement

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