Lean 4 Proof Engineer - Mathematical Formalization
About this role
About the Role What if your deep mathematical expertise could directly shape the future of AI reasoning? We're looking for Lean 4 Proof Engineers to formalize advanced mathematical arguments into machine-verifiable proofs — working at the very frontier of what modern proof assistants can express, capture, and automate. This is a fully remote, flexible contract role built for mathematicians who live at the intersection of rigorous proof construction and formal verification. If you find genuine satisfaction in taking a dense, elegant human argument and expressing it in a form a machine can understand, this role was designed for you. - Organization: Alignerr - Type: Hourly Contract - Location: Remote - Commitment: 10–40 hours/week What You'll Do - Translate informal mathematical proofs into Lean 4 (and related proof systems) with emphasis on clarity, structure, and correctness - Analyze generic and domain-specific proofs — identifying gaps, hidden assumptions, and formalizable sub-structures - Construct formalizations that test the limits of existing proof assistants, especially where automated tools struggle or fail - Collaborate with AI researchers to design, refine, and evaluate strategies for improving formal verification pipelines - Develop highly readable, reproducible proof scripts aligned with mathematical best practices and proof assistant idioms - Provide expert guidance on proof decomposition, lemma selection, and structuring techniques for formal models - Formalize classical proofs and compare machine-verifiable structures against textbook arguments - Investigate where automated provers break down — and articulate precisely why (complexity, missing lemmas, insufficient libraries, etc.) - Create Lean proofs that reveal deeper patterns or generalizations implicit in the original mathematics Who You Are - Hold a Master's degree or higher in Mathematics, Logic, Theoretical Computer Science, or a closely related field - Possess a strong foundation in rigorous proof writing across areas such as algebra, analysis, topology, logic, or discrete mathematics - Have hands-on experience with Lean (Lean 3 or Lean 4), Coq, Isabelle/HOL, Agda, or comparable formal systems — with Lean strongly preferred - Deeply enthusiastic about formal verification, proof assistants, and the future of mechanized mathematics - Able to translate informal mathematical arguments into clean, structured, and machine-checkable formalizations - Comfortable working independently with precision and intellectual rigor Nice to Have - Familiarity with type theory, the Curry-Howard correspondence, and proof automation tools - Experience contributing to large-scale formalization projects such as mathlib - Exposure to theorem provers where automated reasoning frequently fails or requires manual scaffolding - Prior experience with data annotation, data quality, or AI evaluation systems - Strong communication skills for explaining formalization decisions, edge cases, and reasoning strategies Why Join Us - Work on cutting-edge AI projects alongside world-leading research labs - Fully remote and flexible — work when and where it suits you - Freelance autonomy with the structure of meaningful, intellectually stimulating work - Get direct exposure to how advanced AI models are trained and evaluated on mathematical reasoning - Contribute to mapping the frontier of what formal verification can achieve - Potential for ongoing work and contract extension as new projects launch
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