• Background: We identify that current mathematical reasoning approaches either generate creative answers (LLMs) but fail to verify them formally, or verify rigorously (symbolic provers) but cannot efficiently generate answers.
• Contribution:
  • We introduce ECP framework: a modular neuro-symbolic pipeline that integrates a feedback-driven autoformalization stage, LLM-based enumeration and conjecturing, and theorem-proving in Lean.
  • We introduce ConstructiveBench: an autoformalized dataset of 3,431 competition-grade answer-construction problems, each includes informal and formal problem statements, ground-truth answers and metadata, enabling end-to-end formal verification (answer-construction + theorem-proving).

• Location: data/dataset/constructivebench.json
• Description: Curated Olympiad-style problems with metadata and aligned Lean formalizations. Each entry includes:
  • Problem statement
  • Category (e.g., Algebra, Combinatorics)
  • Formal answer in Lean
  • Full formal theorem
  • Answer-construction alignment parts (header, answer, theorem with/without answer)

{
  "name": "IMO2011SLC4",
  "category": "Combinatorics",
  "source": "IMO/2011",
  "problem": "...",
  "answer": "The greatest such number k is 3",
  "formalization": "...",
  "...": "..."
}

Below, we show the problem sources and problem domains in ConstructiveBench.

• Location: data/dataset/putnam.json
• Description: A selected subset of answer-construction problems from the PutnamBench dataset, chosen to evaluate the ECP pipeline on university-level problems.

We show the end-to-end answer-construction ("Conjecturer Model") and theorem proving ("Prover Model") accuracy with Pass@32 metric on 3,431 ConstructiveBench problems, comparing the CoT baseline vs. ECP for answer-construction.

• Python 3.10
• CUDA >= 11.8
• Git LFS
• Lean Proof Assistant
• (Optional) Chrome and Chrome Driver

1. Initialize Git LFS
   (Skip if already set up.)

   git lfs install

2. Install Lean
   (Skip if already set up.)

   curl https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh -sSf | sh
   source ~/.bashrc

   Verify installation:

   lean --version

3. Clone the Repository

   git clone --recursive https://github.com/JackSun200312/ECP
   cd ECP

4. Create a Python Virtual Environment
   We recommend using venv:

   python -m venv imosolver
   source imosolver/bin/activate
   pip install -r requirements.txt

5. Build Lean Environment
   Build for both the newest version and v4.9.0-rc1 (for prover models). This may take around 30 minutes.

   cd Formalization
   lake update
   lake build Main
   cd ..
   
   cd prover/mathlib4
   lake build
   cd ../..

6. Set Up LLM API Keys
   Either add them to your shell file or edit appl.yaml directly:

   echo 'export OPENAI_API_KEY="your_openai_key_here"' >> ~/.bashrc
   echo 'export DEEPSEEK_API_KEY="your_deepseek_key_here"' >> ~/.bashrc
   source ~/.bashrc

ECP/
├── prover/     # Adapted from Goedel-Prover, contains utilities for running prover models
├── src/
│   └── ecp/
│   ├── agent.py    # Multi-agent framework for Enumerate → Conjecture → Prove (ECP)
│   ├── main.py     # Main entry point for experiments
│   └── utils.py    # Utility functions
│   └── scripts/
│   ├── dataset/
│   ├── deploy/
│   ├── finetune/
│   ├── lean/
│   └── trace/
└── data/
    └── dataset/
    ├── constructivebench.json  # ConstructiveBench dataset
    └── putnam.json     # PutnamBench answer-construction subset

The file src/ecp/main.py provides a unified interface for three pipelines:

1. answer_gen: Full ECP pipeline (Enumerate → Conjecture → Verify)
2. autoformalize: Generate Lean formalizations from informal problems/answers
3. proof_gen: Use a formal prover to generate complete Lean proofs

• Use --problem_path to specify the dataset.
  • Main option: constructivebench (recommended)
  • For testing: test (runs a single case)

• Set --mode to one of:
  • answer_gen
  • autoformalize
  • proof_gen

• --enable_enumerator:
  • True: Run full ECP (enumerator + conjurer)
  • False: Skip enumeration (Chain-of-Thought baseline)
• --problem_name:
  • "all" (default) to process all entries
  • Or a comma-separated list of specific problem names

python src/ecp/main.py --mode autoformalize --problem_path constructivebench

python src/ecp/main.py --mode answer_gen --problem_path constructivebench --enable_enumerator true

Output Location:
output/data/dataset/constructivebench.json/deepseek-chat-code/
(To run the CoT baseline, set --enable_enumerator false.)

After generating formalizations and conjectures (via answer_gen), run:

python src/ecp/main.py --mode proof_gen --problem_path constructivebench

Note: Proof generation uses Goedel-Prover by default. You can override with models like deepseek-ai/DeepSeek-Prover-V2-7B or AI-MO/Kimina-Prover-Preview-Distill-7B.

• --enumerator_model: deepseek-chat
• --conjecturer_model: deepseek-chat
• --prover_model: Goedel-LM/Goedel-Prover-SFT
• --max_tokens: 500
• --timeout: 60 (seconds)
• --pass_at_n: 32 (Pass@n metric for proof generation)
• --gpu: 1 (number of GPUs for proof generation)
• --use_embedding_search: False
  (Set to True only if you have GPU resources for embedding-based Lean retrieval.)

You can override any of these options. Check src/ecp/main.py for the full list of arguments.

After experiments, summarize answer/proving accuracies for a dataset (constructivebench, putnam, or test):

python summarize_result.py --base <dataset>

If you find this work useful, please cite:

@misc{sun2025enumerateconjectureproveformallysolvinganswerconstruction,
  title    = {Enumerate-Conjecture-Prove: Formally Solving Answer-Construction Problems in Math Competitions},
  author   = {Jialiang Sun and Yuzhi Tang and Ao Li and Chris J. Maddison and Kuldeep S. Meel},
  year     = {2025},
  eprint   = {2505.18492},
  archivePrefix= {arXiv},
  primaryClass = {cs.AI},
  url  = {https://arxiv.org/abs/2505.18492},
}

The prover part of this repository use code from Goedel-Prover. Some of raw problems from the following datasets were included in ConstructiveBench, as mentioned in the paper:

• Omni-MATH
• OlympiadBench
• MathOdyssey