Recognition: 1 theorem link
· Lean TheoremLeanSearch v2: Global Premise Retrieval for Lean 4 Theorem Proving
Pith reviewed 2026-05-15 02:59 UTC · model grok-4.3
The pith
LeanSearch v2 recovers full premise sets for Lean 4 theorems at 46.1 percent accuracy on research benchmarks.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
LeanSearch v2's reasoning mode recovers 46.1% of ground-truth premise groups within 10 retrieved candidates on a 69-query benchmark of research-level Mathlib theorems, outperforming strong reasoning retrieval systems (38.0%) and premise-selection baselines (9.3%). In a controlled downstream evaluation with a fixed prover loop, replacing alternative retrievers with LeanSearch v2 yields the highest proof success (20% vs. 16% for the next-best system and 4% without retrieval), confirming that retrieval quality propagates to proof generation.
What carries the argument
The reasoning mode's iterative sketch-retrieve-reflect cycles, which operate on top of a standard embedding-reranker pipeline applied to a hierarchy-informalized Mathlib corpus.
Load-bearing premise
The 69-query benchmark and the fixed prover loop are representative of real-world Lean 4 theorem proving tasks.
What would settle it
A larger or differently distributed set of theorems, or the same theorems run inside a changed prover loop, that shows no gain in proof success over the next-best retriever would falsify the claim that the measured retrieval improvement drives the reported proof gains.
Figures
read the original abstract
Proving theorems in Lean 4 often requires identifying a scattered set of library lemmas whose joint use enables a concise proof -- a task we call global premise retrieval. Existing tools address adjacent problems: semantic search engines find individual declarations matching a query, while premise-selection systems predict useful lemmas one tactic step at a time. Neither recovers the full premise set an entire theorem requires. We present LeanSearch v2, a two-mode retrieval system for this task. Its standard mode applies a hierarchy-informalized Mathlib corpus with an embedding-reranker pipeline, achieving state-of-the-art single-query retrieval without domain-specific fine-tuning (nDCG@10 of 0.62 vs. 0.53 for the next-best system). Its reasoning mode builds on standard mode as its retrieval substrate, targeting global premise retrieval through iterative sketch-retrieve-reflect cycles. On a 69-query benchmark of research-level Mathlib theorems, reasoning mode recovers 46.1% of ground-truth premise groups within 10 retrieved candidates, outperforming strong reasoning retrieval systems (38.0%) and premise-selection baselines (9.3%) on the same benchmark. In a controlled downstream evaluation with a fixed prover loop, replacing alternative retrievers with LeanSearch v2 yields the highest proof success (20% vs. 16% for the next-best system and 4% without retrieval), confirming that retrieval quality propagates to proof generation. We have open-sourced all code, data, and benchmarks. Code and data: https://github.com/frenzymath/LeanSearch-v2 . The standard mode is publicly available with API access at https://leansearch.net/ .
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces LeanSearch v2, a two-mode retrieval system for global premise retrieval in Lean 4. Its standard mode uses an embedding-reranker pipeline on a hierarchy-informalized Mathlib corpus to achieve nDCG@10 of 0.62. Its reasoning mode applies iterative sketch-retrieve-reflect cycles on top of the standard mode, recovering 46.1% of ground-truth premise groups within 10 candidates on a 69-query benchmark of research-level theorems (outperforming 38.0% for strong reasoning retrieval systems and 9.3% for premise-selection baselines). In a controlled downstream evaluation with a fixed prover loop, LeanSearch v2 yields 20% proof success versus 16% for the next-best retriever and 4% without retrieval. All code, data, and benchmarks are open-sourced, with a public API available.
Significance. If the empirical results hold, the work makes a clear contribution to automated theorem proving by directly targeting global premise sets rather than isolated lemmas or per-tactic predictions. The reported lift from retrieval quality to proof success (20% vs. 16%) demonstrates practical impact, and the open-sourced code plus public API lower barriers for adoption and extension in the Lean community. The two-mode design offers a reusable substrate for both single-query and iterative reasoning retrieval.
major comments (2)
- The 69-query benchmark evaluation reports 46.1% premise recovery and 20% proof success without variance estimates, statistical significance tests, or sensitivity analysis to query selection or prover-loop parameters. This is load-bearing for the superiority claim over the 38.0% and 16% baselines, as the 8.1-point margins could reflect benchmark construction rather than method robustness.
- The downstream evaluation uses a single fixed prover loop; it is unclear how the 20% success rate changes under alternative loop configurations or theorem distributions, which directly affects the claim that retrieval quality propagates to proof generation.
minor comments (2)
- The abstract introduces the term 'hierarchy-informalized Mathlib corpus' without a brief gloss or pointer to the section that defines the informalization process.
- In the evaluation sections, ensure every baseline system is accompanied by a concise description of its original implementation and any adaptations made for the Lean 4 setting.
Simulated Author's Rebuttal
We thank the referee for the constructive feedback and positive assessment of the work's contribution to global premise retrieval. We address each major comment below and commit to revisions that strengthen the empirical evaluation.
read point-by-point responses
-
Referee: The 69-query benchmark evaluation reports 46.1% premise recovery and 20% proof success without variance estimates, statistical significance tests, or sensitivity analysis to query selection or prover-loop parameters. This is load-bearing for the superiority claim over the 38.0% and 16% baselines, as the 8.1-point margins could reflect benchmark construction rather than method robustness.
Authors: We agree that the absence of variance estimates and statistical tests weakens the robustness claims. In the revised manuscript we will add bootstrap-derived 95% confidence intervals for both the 46.1% premise-recovery and 20% proof-success figures, together with paired significance tests against the reported baselines. We will also include a sensitivity analysis that subsamples the 69-query set and varies prover-loop hyperparameters to show that the observed margins are not artifacts of the particular benchmark construction. revision: yes
-
Referee: The downstream evaluation uses a single fixed prover loop; it is unclear how the 20% success rate changes under alternative loop configurations or theorem distributions, which directly affects the claim that retrieval quality propagates to proof generation.
Authors: The fixed prover loop was selected to isolate the contribution of retrieval quality under identical search and tactic-generation conditions. We acknowledge that broader exploration of loop variants and theorem distributions would further support generalizability. In the revision we will add an explicit discussion of this design choice and, where compute permits, report results on one additional loop configuration to illustrate that the relative ordering among retrievers remains stable. revision: partial
Circularity Check
Empirical retrieval metrics and downstream prover success are direct measurements, not reductions to fitted inputs or self-citations
full rationale
The paper reports nDCG@10, premise-group recovery rates (46.1%), and proof-success percentages (20%) from a fixed 69-query benchmark and a controlled prover loop. These are experimental outcomes obtained by running the described retrieval pipeline and prover on held-out theorems; they are not obtained by solving equations whose right-hand sides are defined from the left-hand sides or from parameters fitted inside the same derivation. The standard mode uses an embedding-reranker pipeline on a hierarchy-informalized corpus, and the reasoning mode iterates sketch-retrieve-reflect on top of it; neither step is shown to presuppose the reported numbers. Self-citations to prior LeanSearch work are present but not load-bearing for the central empirical claims, which remain independently verifiable via the open-sourced code and benchmarks. No uniqueness theorems, ansatzes, or renamings of known results are invoked to force the outcomes.
Axiom & Free-Parameter Ledger
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/* (AbsoluteFloorClosure, Cost, DimensionForcing, AlexanderDuality)reality_from_one_distinction; washburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
global premise retrieval... embedding-reranker pipeline... iterative sketch-retrieve-reflect cycles
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Mm-bright: A multi-task multimodal benchmark for reasoning-intensive retrieval
Abdelrahman Abdallah, Mohamed Darwish Mounis, Mahmoud Abdalla, Mahmoud SalahEldin Kasem, Mostafa Farouk Senussi, Mohamed Mahmoud, Mohammed Ali, Adam Jatowt, and Hyun- Soo Kang. Mm-bright: A multi-task multimodal benchmark for reasoning-intensive retrieval. arXiv preprint arXiv:2601.09562,
-
[2]
Aristotle: IMO-level Automated Theorem Proving
Tudor Achim, Alex Best, Alberto Bietti, Kevin Der, Mathïs Fédérico, Sergei Gukov, Daniel Halpern- Leistner, Kirsten Henningsgard, Yury Kudryashov, Alexander Meiburg, et al. Aristotle: Imo-level automated theorem proving.arXiv preprint arXiv:2510.01346,
work page internal anchor Pith review arXiv
-
[3]
Leanexplore: A search engine for lean 4 declarations.arXiv preprint arXiv:2506.11085,
Justin Asher. Leanexplore: A search engine for lean 4 declarations.arXiv preprint arXiv:2506.11085,
-
[4]
Jiangjie Chen, Wenxiang Chen, Jiacheng Du, Jinyi Hu, Zhicheng Jiang, Allan Jie, Xiaoran Jin, Xing Jin, Chenggang Li, Wenlei Shi, et al. Seed-prover 1.5: Mastering undergraduate-level theorem proving via learning from experience.arXiv preprint arXiv:2512.17260,
-
[5]
Gheorghe Comanici, Eric Bieber, Mike Schaekermann, Ice Pasupat, Noveen Sachdeva, Inderjit Dhillon, Marcel Blistein, Ori Ram, Dan Zhang, Evan Rosen, et al. Gemini 2.5: Pushing the frontier with advanced reasoning, multimodality, long context, and next generation agentic capa- bilities.arXiv preprint arXiv:2507.06261,
work page internal anchor Pith review Pith/arXiv arXiv
-
[6]
Rader: Reasoning-aware dense retrieval models
Debrup Das, Sam O’Nuallain, and Razieh Rahimi. Rader: Reasoning-aware dense retrieval models. InProceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 19981–20008,
work page 2025
-
[7]
A semantic search engine for mathlib4
Guoxiong Gao, Haocheng Ju, Jiedong Jiang, Zihan Qin, and Bin Dong. A semantic search engine for mathlib4. InFindings of the Association for Computational Linguistics: EMNLP 2024, pages 8001–8013, 2024a. Guoxiong Gao, Yutong Wang, Jiedong Jiang, Qi Gao, Zihan Qin, Tianyi Xu, and Bin Dong. Herald: A natural language annotated lean 4 dataset.arXiv preprint a...
-
[8]
doi: 10.1038/ s41586-025-09833-y. Jiedong Jiang, Wanyi He, Yuefeng Wang, Guoxiong Gao, Yongle Hu, Jingting Wang, Nailin Guan, Peihao Wu, Chunbo Dai, Liang Xiao, et al. Fate: A formal benchmark series for frontier algebra of multiple difficulty levels.arXiv preprint arXiv:2511.02872,
-
[9]
Mirb: Mathematical information retrieval benchmark.arXiv preprint arXiv:2505.15585,
Haocheng Ju and Bin Dong. Mirb: Mathematical information retrieval benchmark.arXiv preprint arXiv:2505.15585,
-
[10]
Automated Conjecture Resolution with Formal Verification
Haocheng Ju, Guoxiong Gao, Jiedong Jiang, Bin Wu, Zeming Sun, Leheng Chen, Yutong Wang, Yuefeng Wang, Zichen Wang, Wanyi He, et al. Automated conjecture resolution with formal verification.arXiv preprint arXiv:2604.03789,
work page internal anchor Pith review Pith/arXiv arXiv
-
[11]
Julian Killingback and Hamed Zamani. Benchmarking information retrieval models on complex retrieval tasks.arXiv preprint arXiv:2509.07253,
-
[12]
Junqi Liu, Zihao Zhou, Zekai Zhu, Marco Dos Santos, Weikun He, Jiawei Liu, Ran Wang, Yun- zhou Xie, Junqiao Zhao, Qiufeng Wang, et al. Numina-lean-agent: An open and general agentic reasoning system for formal mathematics.arXiv preprint arXiv:2601.14027,
-
[13]
GroupRank: A Groupwise Paradigm for Effective and Efficient Passage Reranking with LLMs
Meixiu Long, Duolin Sun, Dan Yang, Yihan Jiao, Lei Liu, Jiahai Wang, BinBin Hu, Yue Shen, Jie Feng, Zhehao Tan, et al. Grouprank: A groupwise paradigm for effective and efficient passage reranking with llms.arXiv:2511.11653, 2025a. Meixiu Long, Duolin Sun, Dan Yang, Junjie Wang, Yecheng Luo, Yue Shen, Jian Wang, Hualei Zhou, Chunxiao Guo, Peng Wei, et al....
work page internal anchor Pith review Pith/arXiv arXiv
-
[14]
Mteb: Massive text em- bedding benchmark
Niklas Muennighoff, Nouamane Tazi, Loïc Magne, and Nils Reimers. Mteb: Massive text em- bedding benchmark. InProceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics, pages 2014–2037,
work page 2014
-
[15]
Job Petrovˇciˇc, David Eliecer Narvaez Denis, and Ljup ˇco Todorovski. Combining textual and struc- tural information for premise selection in lean.arXiv preprint arXiv:2510.23637,
-
[16]
ZZ Ren, Zhihong Shao, Junxiao Song, Huajian Xin, Haocheng Wang, Wanjia Zhao, Liyue Zhang, Zhe Fu, Qihao Zhu, Dejian Yang, et al. Deepseek-prover-v2: Advancing formal mathematical rea- soning via reinforcement learning for subgoal decomposition.arXiv preprint arXiv:2504.21801,
work page internal anchor Pith review arXiv
-
[17]
Reasonir: Training retrievers for reasoning tasks.arXiv preprint arXiv:2504.20595,
Rulin Shao, Rui Qiao, Varsha Kishore, Niklas Muennighoff, Xi Victoria Lin, Daniela Rus, Bryan Kian Hsiang Low, Sewon Min, Wen-tau Yih, Pang Wei Koh, et al. Reasonir: Training retrievers for reasoning tasks.arXiv preprint arXiv:2504.20595,
-
[18]
REAL‑Prover: Retrieval Aug- mented Lean Prover for Mathematical Reasoning, 2025
Ziju Shen, Naohao Huang, Fanyi Yang, Yutong Wang, Guoxiong Gao, Tianyi Xu, Jiedong Jiang, Wanyi He, Pu Yang, Mengzhou Sun, et al. Real-prover: Retrieval augmented lean prover for mathematical reasoning.arXiv preprint arXiv:2505.20613,
-
[19]
Hongjin Su, Howard Yen, Mengzhou Xia, Weijia Shi, Niklas Muennighoff, Han-yu Wang, Haisu Liu, Quan Shi, Zachary S Siegel, Michael Tang, et al. Bright: A realistic and challenging bench- mark for reasoning-intensive retrieval.arXiv preprint arXiv:2407.12883,
-
[20]
11 Yicheng Tao, Haotian Liu, Shanwen Wang, and Hongteng Xu. Learning an effective premise re- trieval model for efficient mathematical formalization.arXiv preprint arXiv:2501.13959,
-
[21]
Kimi K2: Open Agentic Intelligence
Kimi Team, Yifan Bai, Yiping Bao, Y Charles, Cheng Chen, Guanduo Chen, Haiting Chen, Huarong Chen, Jiahao Chen, Ningxin Chen, et al. Kimi k2: Open agentic intelligence.arXiv preprint arXiv:2507.20534,
work page internal anchor Pith review Pith/arXiv arXiv
-
[22]
The mathlib Community. The Lean mathematical library. InProceedings of the 9th ACM SIGPLAN International Conference on Certified Programs and Proofs (CPP 2020), pages 367–381. ACM,
work page 2020
-
[23]
In: Proceedings of the 9th ACM SIGPLAN International Conference on Certified Programs and Proofs
doi: 10.1145/3372885.3373824. Sean Welleck, Jiacheng Liu, Ronan Le Bras, Hannaneh Hajishirzi, Yejin Choi, and Kyunghyun Cho. Naturalproofs: Mathematical theorem proving in natural language.arXiv preprint arXiv:2104.01112,
-
[24]
Rank1: Test-time compute for reranking in information retrieval.arXiv preprint arXiv:2502.18418,
Orion Weller, Kathryn Ricci, Eugene Yang, Andrew Yates, Dawn Lawrie, and Benjamin Van Durme. Rank1: Test-time compute for reranking in information retrieval.arXiv preprint arXiv:2502.18418,
-
[25]
An Yang, Anfeng Li, Baosong Yang, Beichen Zhang, Binyuan Hui, Bo Zheng, Bowen Yu, Chang Gao, Chengen Huang, Chenxu Lv, et al. Qwen3 technical report.arXiv preprint arXiv:2505.09388,
work page internal anchor Pith review Pith/arXiv arXiv
-
[26]
Qwen3 Embedding: Advancing Text Embedding and Reranking Through Foundation Models
URLhttps://github.com/yaoyichen/ INF-X-Retriever. Yanzhao Zhang, Mingxin Li, Dingkun Long, Xin Zhang, Huan Lin, Baosong Yang, Pengjun Xie, An Yang, Dayiheng Liu, Junyang Lin, et al. Qwen3 embedding: Advancing text embedding and reranking through foundation models.arXiv preprint arXiv:2506.05176,
work page internal anchor Pith review Pith/arXiv arXiv
-
[27]
Premise Selection for a Lean Hammer
Thomas Zhu, Joshua Clune, Jeremy Avigad, Albert Qiaochu Jiang, and Sean Welleck. Premise selection for a lean hammer.arXiv preprint arXiv:2506.07477,
-
[28]
12 A Benchmark Curation In this section, we present the curation methodology, key characteristics, and illustrative examples of our benchmark to provide readers with a clearer understanding of both the benchmark and the experimental results. We introduce two benchmarks:MathlibQRfor the classical formal theorem searching task, andMathlibMPRfor global premi...
work page 2024
-
[29]
Table 5: Mean rank conditioned on the system’s randomized label position
— but the permutation procedure assigns each system to each of the four label positions approximately equally often (574–640assignments per cell on2430judg- ments; uniform expectation is607.5), so the bias averages out at the system level and the reported overall mean ranks are debiased. Table 5: Mean rank conditioned on the system’s randomized label posi...
work page 2025
-
[30]
21 Table 10:MathlibQR by difficulty.Half the queries are Easy, half are Hard
Throughout the following tables we abbreviate column headers asLE= LeanEx- plore,LF= LeanFinder,LSv2(r)= LeanSearch v2 retriever-only, andLSv2(rr)= LeanSearch v2 with reranking. 21 Table 10:MathlibQR by difficulty.Half the queries are Easy, half are Hard. nDCG@10Recall@10 Difficulty LE LF LSv2(r) LSv2(rr) LE LF LSv2(r) LSv2(rr) Easy 0.410 0.568 0.5330.666...
-
[31]
Best per column inbold. Covered (main only) Covered (main∨alt-all) System 5 10 20 30 50 5 10 20 30 50 Reasoning retrieval (informal+formal query) INF-X-Retriever 14.5 17.4 18.8 21.7 21.7 15.9 18.8 21.7 24.6 24.6 +query rewriter 10.1 10.1 14.5 15.9 23.2 10.1 10.1 17.4 17.4 24.6 ReasonIR 15.9 17.4 18.8 18.8 26.1 17.4 18.8 20.3 21.7 30.4 DIVER (full pipeline...
-
[32]
Table 16:Prover-backbone ablation on FATE-H.Each cell is the count of solved problems out of 100(percentages in parentheses). The Sonnet column reproduces the L0 / L1 / reasoning-mode rows of Table 3; the Kimi column re-runs the same loops with Kimi K2 Instruct in the prover role only. Retrieval mode (prover input) Sonnet prover Kimi prover No retrieval 4...
work page 2020
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.