About the job
Mercor connects elite creative and technical talent with leading AI research labs. Headquartered in San Francisco, our investors include Benchmark , General Catalyst , Peter Thiel , Adam D'Angelo , Larry Summers , and Jack Dorsey .
Position: Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving)
Type: Contract
Compensation: $90–$110/hour
Location: Remote
Commitment: 20–40 hours/week
Role Responsibilities
- Write correct, idiomatic Lean 4 statements and proofs that compile against current mathlib . Cover areas such as algebra, analysis, number theory, combinatorics, and logic.
- Formalize natural-language mathematics from competition problems and textbook results to research-level lemmas. Ensure the formal statement matches the original.
- Review AI-generated Lean statements and proofs. Identify failures or incorrect proofs and provide clear, specific written feedback.
- Help define guidelines and rubrics for proof quality, statement fidelity, and mathlib conventions.
- Collaborate with other Lean engineers and the lab's researchers to maintain consistent standards and elevate quality.
Qualifications
Must-Have
- Hands-on experience writing formal proofs in Lean 4 . Examples include mathlib contributions, a formalization project, or a Lean library or tool.
- Comfort with mathlib and Lean 4 tactics. Ability to find and use the right lemmas.
- Strong background in proof-based mathematics, theoretical computer science, or logic through a degree or research record.
- Ability to turn a written statement and proof into a correct formal statement and a proof that checks.
- Engage reliably for at least 20 hours/week during weekdays.
- Clear written communication and ability to explain proof strategy and formalization choices precisely.
Preferred
- Experience with other proof assistants or dependently typed languages ( Coq/Rocq , Isabelle , Agda , Haskell ).
- Experience with Lean metaprogramming or AI-for-math work such as LLM provers , Lean agent environments, or benchmarks like miniF2F , ProofNet , or PutnamBench .
Compensation & Legal
- W-2 employment with Cincinnatus LLC .
- Equal Employment Opportunity employer.
Application Process (Takes 20–30 mins to complete)
- Upload resume
- AI interview based on your resume
- Submit form
Resources & Support
- For details about the interview process and platform information, please check:
- For any help or support, reach out to: [email protected]
PS: Our team reviews applications daily. Please complete your AI interview and application steps to be considered for this opportunity.