Lean 4 Theorem Prover Engineer for AI Math Formalization

Mercor; United States; Remote; USD 62,000 - 104,000; Part time

Job summary

Mercor is seeking Lean engineers and formal mathematicians to help state and prove mathematics for AI models using Lean 4 and mathlib. You will write Lean proofs, translate informal math into precise formal statements, and assess model proofs for fidelity.

This is a part-time role (20–40 hours/week) with W-2 employment through an international entity, offering collaboration with a leading AI lab and opportunities to contribute to high‑quality formalization work.

Qualifications

• Hands-on experience writing formal proofs in Lean 4 (mathlib contributions or projects).
• Ability to turn written statements into correct formal proofs that check.
• Strong background in proof-based mathematics or logic through degree or research.
• Willingness to commit at least 20 hours per week and communicate clearly.

Responsibilities

• Write correct Lean 4 statements and proofs that compile against mathlib.
• Formalize natural-language mathematics into precise formal statements.
• Review AI-generated Lean proofs and provide clear feedback.
• Help define guidelines and rubrics for proof quality and fidelity.
• Collaborate with Lean engineers and researchers to raise standards.

Skills

Lean 4

Formal proofs

Math background

Formalization

Communication

Education

Degree in mathematics / logic / CS

Tools

mathlib

Lean 4 tooling

Job description

Mercor is seeking Lean engineers and formal mathematicians to help state and prove mathematics for AI models using Lean 4 and mathlib. You will write Lean proofs, translate informal math into precise formal statements, and assess model proofs for fidelity.

This is a part-time role (20–40 hours/week) with W-2 employment through an international entity, offering collaboration with a leading AI lab and opportunities to contribute to high‑quality formalization work.