Highlights
- State-of-the-art among open-weight whole-proof provers. OProver-32B
attains the best Pass@32 on MiniF2F (93.3), ProverBench (58.2), and
PutnamBench (11.3), and the second-best on MathOlympiad (22.8) and
ProofNet (33.2). Even OProver-8B beats Goedel-Prover-V2-32B on all five
benchmarks despite having 4× fewer parameters.
- Agentic proving is in the policy, not bolted on. Retrieval, multi-turn
compiler feedback, and iterative repair are all part of the trained policy.
Ablations show feedback is the dominant driver: removing it costs OProver-32B
4.9–7.4 Pass@32 points across benchmarks; removing retrieval on top adds
0.5–1.7 more.
- Co-evolving prover and corpus. Each post-training iteration runs agentic
rollouts; verified proofs are added to OProofs and re-indexed for retrieval,
repair trajectories become SFT data, and unresolved hard cases provide RL
signal. MiniF2F-Test Pass@32 grows monotonically: OProver-8B 79.5 → 86.2 →
87.0 → 91.8 across rounds; OProver-32B 84.7 → 88.1 → 93.3.
What's in this release
The OProver collection (m-a-p/OProver) bundles the paper,
the corpus, and seven model checkpoints covering both training stages and
both model sizes:
Use OProver-8B or OProver-32B for proving. The Base / Round-N
checkpoints are released for reproducibility and ablation studies.
Dataset: OProofs
OProofs is a large-scale Lean 4 corpus that doubles as the retrieval memory at
proving time. It is built from three sources: public Lean resources
(NuminaMath-LEAN, Lean-Workbook, Leanabell-FormalStmt, Goedel-Pset, …),
large-scale autoformalization + agentic proof synthesis from informal math
mined on Common Crawl and GitHub, and traces from OProver's own agentic
proving runs.

Training
Two stages, both anchored on OProofs.
1. Continued pretraining (one-time). A 65B-token mixture of formal
Lean (≈30%, from OProofs), code (≈20%, OpenCoder), mathematics (≈40%,
Nemotron-Math-4-Plus), and long-CoT (≈10%, ProLong-64K). AdamW, peak LR
5e-5, cosine with 3% warmup, batch 512, sequence length 8192. Output:
OProver-{8B,32B}-Base.
2. Iterative post-training. Each round runs:
- Agentic proving with the current prover on a theorem pool, producing
multi-round rollouts conditioned on retrieved proofs and Lean feedback.
- SFT on round-level repair examples
(s, R, p_{t-1}, f_{t-1}) → p_t,
with cross-entropy loss only on the new attempt.
- GSPO RL on hard cases (groups with non-trivial pass-rate). Per-round
reward
r = 0.8 + 0.2·1[format ok] if Lean-verified, else 0; advantages
are pooled across the n×R rounds for the same theorem.
- Newly verified proofs and repair trajectories are folded back into OProofs
and re-indexed into the retrieval memory for the next round.
Results
Pass@32 (n=64) across five Lean 4 benchmarks. Bold is best, underlined
is second-best.

OProver-32B reaches three best and two second-best across five benchmarks —
the most top placements of any model in the comparison, despite being a
32B dense model versus a 560B MoE or a 671B dense competitor.
Loading
from transformers import AutoModelForCausalLM, AutoTokenizer
name = "m-a-p/OProver-8B"
tok = AutoTokenizer.from_pretrained(name)
model = AutoModelForCausalLM.from_pretrained(name, torch_dtype="bfloat16", device_map="auto")
from datasets import load_dataset
ds = load_dataset("m-a-p/OProofs", split="train")
OProver is trained against a multi-round agentic interface: at each round the
input includes the target Lean statement, top-k retrieved verified proofs, the
prior proof attempt, and the Lean compiler feedback. See the paper §2.1 for
the prompt template, and Appendix B for serialization details.
Citation
@article{ma2026oprover,
title = {OProver: A Unified Framework for Agentic Formal Theorem Proving},
author = {David Ma and Kaijing Ma and Shawn Guo and Yunfeng Shi and Enduo Zhao and Jiajun Shi and Zhaoxiang Zhang and Gavin Cheung and Jiaheng Liu and Zili Wang},
journal = {arXiv preprint arXiv:2605.17283},
year = {2026}
}