Lean Engineer, Formal Mathematics, Lean 4, Mathlib, Theorem Proving

Job Description:

• Write correct, idiomatic Lean 4 statements and proofs that compile against current mathlib
• Formalize natural-language mathematics, including competition problems, textbook results, and research-level lemmas
• Review AI-generated Lean statements and proofs, identify failures or incorrect results, and provide specific written feedback
• Help define guidelines and rubrics for proof quality, statement fidelity, and mathlib conventions
• Collaborate with Lean engineers and researchers to maintain consistent standards and improve quality
• Work on projects training and enhancing AI systems

Requirements:

• Hands-on experience writing formal proofs in Lean 4
• Comfort with mathlib and Lean 4 tactics, including finding and using appropriate lemmas
• Strong background in proof-based mathematics, theoretical computer science, or logic through a degree or research record
• Ability to turn written statements and proofs into correct formal statements and checking proofs
• Availability for at least 20 hours per week during weekdays, with reliable engagement
• Clear written communication and ability to explain proof strategy and formalization choices precisely
• Nice to have: experience with Coq/Rocq, Isabelle, Agda, Haskell, Lean metaprogramming, or AI-for-math work
• Must not require H1-B or STEM OPT sponsorship/support at this time

Benefits:

• W-2 employment with payroll, benefits, and compliance through Cincinnatus LLC (or appropriate international entity)
• Fully remote work
• Flexible schedule; work can be completed on your own schedule
• Weekly payments via Stripe or Wise based on services rendered
• Opportunity to collaborate with leading researchers
• Referral payments of up to $1,760 for each successful referral, subject to limits