Remote Lean 4 Theorem Prover & Formal Math Engineer

mercor; United States; Remote; USD 124,000 - 152,000; Full time

Job summary

Mercor seeks a Lean Engineer specializing in Formal Mathematics to develop rigorous Lean 4 proofs. This remote contract role offers 20–40 hours per week and flexible scheduling for researchers who value precision.

You will write Lean 4 proofs, formalize results from problems and textbooks, review AI-generated proofs, and help define rubrics for proof quality and mathlib conventions. Collaboration with Lean engineers and researchers will elevate overall standards.

Qualifications

• 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.

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.

Skills

Lean 4

Mathlib

Theorem Proving

Lean tactics

Formal proofs

Tools

Coq

Isabelle

Agda

Haskell

Job description

Mercor seeks a Lean Engineer specializing in Formal Mathematics to develop rigorous Lean 4 proofs. This remote contract role offers 20–40 hours per week and flexible scheduling for researchers who value precision.

You will write Lean 4 proofs, formalize results from problems and textbooks, review AI-generated proofs, and help define rubrics for proof quality and mathlib conventions. Collaboration with Lean engineers and researchers will elevate overall standards.