Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving)
Mercor Experts · Remote · Writing / editing
Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving) is an open role at Mercor Experts, available remotely, with pay listed as $90–$110/hr.
Applications open on Mercor Experts’ own site. How we make money.
At a glance
- Pay
- $90–$110/hrStated by Mercor Experts
- Location
- Remote
- Time commitment
- Part-time, minimum 20 hours weekly, expandable to 40
- Experience
- Hands-on Lean 4 formal proof writing
- Work type
- Writing / editing
- Field
- Science / STEM
- Listed
- Since Sep 30, last confirmed Oct 22
The work
Author and check Lean 4 proofs, and convert informal mathematics into exact formal statements.
What you would do
- Produce Lean 4 theorems and their proofs that build with the latest mathlib
- Convert plain-language math, from contest problems to research lemmas, into formal statements
- Examine model-produced Lean output, locate errors or mis-stated claims, and write specific feedback
You're a fit if you
- have practical background writing Lean 4 formal proofs
- are at ease with the mathlib library and Lean 4's tactic language
- can articulate whether a formalization captures the original or is subtly flawed
Summarised by HumanSourcer from Mercor Experts’ listing. Check the listing before you apply.
How the pay compares
Higher than 73% of the 107 distinct hourly rates advertised for Science / STEM roles right now. Hourly USD, top of each advertised range, one count per distinct rate. Same method as the Pay Index.
From Mercor Experts’ listing
“Help a leading AI lab teach its models to write real, machine-checked mathematics in Lean. A leading AI lab is looking for Lean engineers, formal mathematicians and proof engineers to help its AI models state and prove mathematics correctly.”
About Mercor Experts: how it pays, how to get in, and what to know first. Read the guide →
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Frequently asked questions
How do I apply for the Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving) role at Mercor Experts?
Applications go through Mercor Experts's own portal - HumanSourcer links to the listing and never collects applications or handles hiring. Mercor Experts's access model is "Apply" (Profile / role application). This listing was first seen here on September 30, 2026 and was still live at the last check.
Is the Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving) role at Mercor Experts remote?
Yes - Mercor Experts lists this role as remote.
What does the Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving) role at Mercor Experts pay?
Mercor Experts lists this role's pay as $90–$110/hr, quoted from the listing rather than estimated.
What kind of work is Lean Engineer, Formal Mathematics (Lean 4, Mathlib, Theorem Proving)?
Writing / editing. Law, medicine, finance, engineering, operations and AI evaluation
Is Mercor Experts a legitimate AI-training platform?
Direct expert network - and that relationship is rated "Confirmed" here because it can be checked against www.mercor.com rather than taken on Mercor Experts's word. Confidence describes how well the ownership is evidenced. It is not a rating of how the platform treats the people who work for it, which no public source covers reliably.
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