| --- |
| base_model: Qwen/Qwen3.5-2B |
| pipeline_tag: text-generation |
| tags: |
| - base_model:adapter:Qwen/Qwen3.5-2B |
| - lora |
| - transformers |
| - lean4 |
| - theorem-proving |
| - tactic-prediction |
| - formal-verification |
| - mathlib |
| - peft |
| license: mit |
| datasets: |
| - markm39/openproof-tactic-pairs |
| --- |
| |
| # OpenProof Tactic 2B |
|
|
| A Lean 4 tactic prediction model fine-tuned from [Qwen/Qwen3.5-2B](https://huggingface.co/Qwen/Qwen3.5-2B) on 190K+ Mathlib tactic pairs. |
|
|
| Given a Lean 4 proof goal state, the model predicts the next tactic to apply. Designed for use in best-first search (BFS) proof engines like [OpenProof](https://github.com/mxthematic/openproof). |
|
|
| ## Usage |
|
|
| ```python |
| from transformers import AutoModelForCausalLM, AutoTokenizer |
| from peft import PeftModel |
| import torch |
| |
| base = "Qwen/Qwen3.5-2B" |
| tokenizer = AutoTokenizer.from_pretrained(base) |
| model = AutoModelForCausalLM.from_pretrained(base, torch_dtype=torch.bfloat16, device_map="cuda") |
| model = PeftModel.from_pretrained(model, "markm39/openproof-tactic-2b") |
| |
| # Input: goal state followed by ::: |
| prompt = "n m : Nat\\n⊢ n + m = m + n:::" |
| inputs = tokenizer(prompt, return_tensors="pt").to("cuda") |
| with torch.no_grad(): |
| out = model.generate(**inputs, max_new_tokens=64, do_sample=True, temperature=0.6, top_k=10) |
| print(tokenizer.decode(out[0][inputs.input_ids.shape[1]:], skip_special_tokens=True)) |
| # Output: induction m with | zero => simp | succ m ih => simp [Nat.add_assoc, ih, Nat.add_comm] |
| ``` |
|
|
| ## Training |
|
|
| - **Base model**: Qwen/Qwen3.5-2B |
| - **Method**: SFT with LoRA (rank 64, alpha 128) |
| - **Trainable params**: 43.6M / 1.93B (2.3%) |
| - **Data**: [markm39/openproof-tactic-pairs](https://huggingface.co/datasets/markm39/openproof-tactic-pairs) -- 190K+ Lean 4 goal-tactic pairs extracted from Mathlib |
| - **Input format**: `{goal_state}:::` |
| - **Output format**: tactic string |
| - **Epochs**: ~1.8 (12,500 steps) |
| - **Batch size**: effective 128 (2 per device x 32 gradient accumulation) |
| - **Learning rate**: 2e-5 cosine schedule |
| - **Best eval loss**: 0.5492 (checkpoint-12500) |
| - **Hardware**: RunPod GPU instance |
| - **Framework**: HuggingFace TRL + PEFT |
|
|
| ## Intended Use |
|
|
| Tactic prediction for automated theorem proving in Lean 4. The model generates candidate tactics given a proof goal state, which are then verified by the Lean type checker. Designed to be used with beam search -- sample multiple candidates and verify each. |
|
|
| Not intended for general-purpose text generation. |
|
|
| ## Limitations |
|
|
| - Trained on Mathlib tactics only -- may not generalize to custom Lean libraries |
| - LoRA adapter (must be loaded on top of Qwen3.5-2B base) |
| - SFT only (no RL/GRPO refinement yet) |
| - May hallucinate lemma names that don't exist in Mathlib |
|
|
| ## Links |
|
|
| - [OpenProof](https://github.com/mxthematic/openproof) -- the theorem prover that uses this model |
| - [Training code](https://github.com/mxthematic/openproof-ml) |
| - [Training data](https://huggingface.co/datasets/markm39/openproof-tactic-pairs) |
|
|
| ## Acknowledgments |
|
|
| Training data derived from [LeanDojo](https://leandojo.org/) (Yang et al.), [Lean Workbook](https://huggingface.co/datasets/internlm/Lean-Workbook) (InternLM), and [Goedel-Pset](https://huggingface.co/datasets/Goedel-LM/Goedel-Pset) (Goedel-LM). Tactic extraction from whole proofs uses [Pantograph](https://github.com/leanprover/Pantograph) kernel-level invocations. |
|
|