HyperTree Proof Search for Neural Theorem Proving
Written for the Research library (claude-opus-5-5) from the paper text. Original — arxiv.org/pdf/2205.11491v1
Summary
Automated provers for formal mathematics have to pick tactics from an unbounded space and then close every subgoal a tactic creates. That makes search methods built for two-player games a poor fit. The authors, from Meta AI Research, built a prover called Evariste around HyperTree Proof Search (HTPS), a search procedure modelled on AlphaZero. Instead of following single paths, HTPS expands whole proof hypertrees. A transformer policy suggests tactics, and a critic estimates how likely each goal is to be provable. Both models keep learning online from ongoing searches rather than through separate expert-iteration rounds. The experiments use Metamath (set.mm), Lean with Mathlib, and Equations, a new lightweight environment for proving identities. HTPS on its own beats GPT-f on held-out Metamath theorems, and online training raises accuracy much further. In Lean, the system also sets new best results on miniF2F. The work matters because it shows that search combined with continual learning lets neural provers solve problems well outside their supervised training data. That could cut the human effort needed to formalize mathematics.
Key points
- On held-out set.mm theorems in Metamath, a model trained only on annotated proofs plus HTPS proves 65.4%, compared with GPT-f's 56.5%. Online training on the unsolved theorems raises this to 82.6%.
- In Lean, with a similar compute budget, accuracy on miniF2F-curriculum goes from 31% to 42%, and the model reaches 58.6% on miniF2F-valid.
- Three environments are used: Metamath (about 30k theorems in set.mm), Lean (about 27k in Mathlib) and Equations, a new environment built for quick prototyping.
- Ablations show that training the policy only on minimal proofs works best (78.1% vs 40.6% on Equations). A soft critic beats both a hard critic and having no critic: removing the critic costs 5.2 points on Metamath and 12.5 on Equations.
- Refreshing the provers' models more often gives better results over time, which supports online training over expert iteration.
Cited by
- Llemma: An Open Language Model For Mathematics
- ProofNet: Autoformalizing and Formally Proving Undergraduate-Level Mathematics
- Draft, Sketch, and Prove: Guiding Formal Theorem Provers with Informal Proofs
- Augmented Language Models: a Survey
- Tool Learning with Foundation Models
- DeepSeek-Prover-V2: Advancing Formal Mathematical Reasoning via Reinforcement Learning for Subgoal Decomposition
- DeepSeek-Prover: Advancing Theorem Proving in LLMs through Large-Scale Synthetic Data
- DeepSeek-Prover-V1.5: Harnessing Proof Assistant Feedback for Reinforcement Learning and Monte-Carlo Tree Search
- LeanDojo: Theorem Proving with Retrieval-Augmented Language Models
Cite
@misc{lample2022hypertree,
title = {{HyperTree Proof Search for Neural Theorem Proving}},
author = {Lample, Guillaume and Lachaux, Marie-Anne and Lavril, Thibaut and Martinet, Xavier and Hayat, Amaury and Ebner, Gabriel and Rodriguez, Aurélien and Lacroix, Timothée},
year = {2022},
doi = {10.48550/arxiv.2205.11491},
eprint = {2205.11491},
archivePrefix = {arXiv},
url = {https://doi.org/10.48550/arxiv.2205.11491}
}References
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