Lean 4 programmer

Moleculyst · India

Company Description

Moleculyst Ventures Private Limited is an AI research and engineering company focused on building reliable, autonomous, and self-improving AI systems. Our work includes LLM reasoning, hallucination detection, automated research pipelines, interpretability, formal verification, and systems that can evaluate and improve their own problem-solving procedures.

We are particularly interested in combining modern language models with rigorous mathematical and computational tools. One area of our work involves integrating formal theorem provers such as Lean 4 into AI systems so that mathematical reasoning and generated proofs can be mechanically verified rather than accepted solely on the basis of model output.

Role Description

We are looking for a Lean 4 Programmer to work on formal theorem proving and its integration with AI systems.

The role will involve writing and verifying formal proofs in Lean 4, working with Mathlib, understanding and manipulating proof states, and developing infrastructure that allows AI models to generate, test, repair, and verify formal proofs.

You will collaborate with our AI research and engineering team on systems where language models interact programmatically with Lean. Depending on experience and interests, the work may also involve tactic development, Lean metaprogramming, automated theorem proving, proof-search systems, dataset generation, and evaluation of LLM mathematical reasoning.

This is a part-time, remote role with flexible working hours and regular online collaboration with the research team.

Responsibilities

• Write, debug, and maintain formal proofs in Lean 4 .
• Work extensively with Mathlib and existing Lean libraries.
• Formalize mathematical statements and translate informal proofs into machine-checkable Lean proofs.
• Diagnose proof failures and work effectively with Lean proof states, goals, tactics, and error messages.
• Help build interfaces between LLMs and the Lean 4 theorem prover .
• Develop methods for automatically generating, checking, repairing, and evaluating proofs.
• Contribute reusable Lean code, tactics, utilities, and formalization infrastructure.
• Review generated proofs for correctness, maintainability, and appropriate use of Mathlib.
• Collaborate with researchers working on automated reasoning, AI evaluation, and autonomous research systems.
• Document formalizations, experiments, and technical workflows clearly.

Qualifications

• Practical experience with Lean 4 .
• Familiarity with Mathlib and Lean's tactic/proof ecosystem.
• Strong understanding of mathematical proofs, logic, or discrete mathematics.
• Comfortable programming and debugging formal proofs rather than only writing informal mathematics.
• Familiarity with concepts from type theory, formal methods, theorem proving, or proof assistants .
• Experience with Lean metaprogramming, tactic development, automated theorem proving, or proof search is a strong advantage.
• Experience with other proof assistants such as Coq, Isabelle, Agda, or HOL is useful, but Lean 4 experience is strongly preferred.
• Programming experience in Python or another general-purpose language is beneficial, particularly for integrating Lean with external systems.
• Interest in LLMs, automated reasoning, AI-assisted mathematics, or formal verification is highly desirable.
• Ability to work independently, communicate technical ideas clearly, and collaborate effectively in a remote research environment.
• Students, researchers, open-source contributors, and experienced Lean developers are all encouraged to apply. Contributions to Mathlib or other formalization projects are particularly valued.