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

🔥 3 minutes ago

🇺🇸 United States – Remote

💵 $90 - $110 / hour

⏱ Part Time

🟡 Mid-level

🟠 Senior

👷🏻‍♀️ Engineer

👻 Ghost score 8%

What it means: how likely this posting is sitting open without active hiring.How to read it: 60% or higher means we think this is a ghost. Lower scores are less of a worry.How we score it: age, reposts, open roles vs team size, how fast jobs close, and whether pay is listed.Fine print: an estimate from public data, not a judgment of the company. Real jobs can score high, so treat it as a hint, not a fact.

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Mercor

WebsiteLinkedInAll Job Openings

51 - 200 employees

Founded 2023

🔥 Funding within the last year

💰 $350M Series C - Mercor on 2025-10

Mercor is a company for which no descriptive text was provided in the input. Additional information (products, services, target customers, or industry specifics) is needed to create an accurate summary and select appropriate industries.

📋 Description

• Write correct, idiomatic Lean 4 statements and proofs compiling 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 proofs that establish the wrong thing and provide clear written feedback • Help define guidelines and rubrics for proof quality, statement fidelity, and mathlib conventions • Collaborate with Lean engineers and lab researchers to maintain consistent standards • 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 convert written statements and proofs into correct formal statements and checking proofs • Availability for at least 20 hours per week during weekdays • 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 • Unable to support H1-B or STEM OPT candidates at this time

🏖️ Benefits

• W-2 employment with Cincinnatus LLC (or appropriate international entity) • Payroll, benefits, and compliance provided by the employer of record • Fully remote work • Flexible schedule / work on your own schedule • Weekly payments via Stripe or Wise • Opportunity to collaborate with leading researchers • Referral payments of up to $1,760 for each successful referral