Growing Mathlib: maintenance of a large scale mathematical library
Published: Aug 29, 2025
Last Updated: Aug 29, 2025
Authors:Anne Baanen, Matthew Robert Ballard, Johan Commelin, Bryan Gin-ge Chen, Michael Rothgang, Damiano Testa
Abstract
The Lean mathematical library Mathlib is one of the fastest-growing libraries of formalised mathematics. We describe various strategies to manage this growth, while allowing for change and avoiding maintainer overload. This includes dealing with breaking changes via a deprecation system, using code quality analysis tools (linters) to provide direct user feedback about common pitfalls, speeding up compilation times through conscious library (re-)design, dealing with technical debt as well as writing custom tooling to help with the review and triage of new contributions.