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Lean mathlib

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Mathlib is a user maintained library for the Lean theorem prover. It contains both programming infrastructure and mathematics, as well as tactics that use the former and allow to develop the latter.


You can find detailed instructions to install Lean, mathlib, and supporting tools on our website.


Got everything installed? Why not start with the tutorial project?

For more pointers, see Learning Lean.


Besides the installation guides above and Lean's general documentation, the documentation of mathlib consists of:

Much of the discussion surrounding mathlib occurs in a Zulip chat room. Since this chatroom is only visible to registered users, we provide an openly accessible archive of the public discussions. This is useful for quick reference; for a better browsing interface, and to participate in the discussions, we strongly suggest joining the chat. Questions from users at all levels of expertise are welcomed.


The complete documentation for contributing to mathlib is located on the community guide contribute to mathlib

The process is different from other projects where one should not fork the repository. Instead write permission for non-master branches should be requested on Zulip by introducing yourself, providing your GitHub handle and what contribution you are planning on doing.


Mathlib has the following guidelines and conventions that must be followed

Note: the title of a PR should follow the commit naming convention.

Using leanproject to contribute

Running the leanproject get -b mathlib:shiny_lemma command will create a new worktree mathlib_shiny_lemma with a local branch called shiny_lemma which has a copy of mathlib to work on.

leanproject build will check that nothing broke. Be warned that this will take some time if a fundamental file was changed.


  • Anne Baanen (@Vierkantor): algebra, number theory, tactics
  • Reid Barton (@rwbarton): category theory, topology
  • Riccardo Brasca (@riccardobrasca): algebra, number theory, algebraic geometry, category theory
  • Mario Carneiro (@digama0): lean formalization, tactics, type theory, proof engineering
  • Bryan Gin-ge Chen (@bryangingechen): documentation, infrastructure
  • Johan Commelin (@jcommelin): algebra, number theory, category theory, algebraic geometry
  • Rémy Degenne (@RemyDegenne): probability, measure theory, analysis
  • Floris van Doorn (@fpvandoorn): measure theory, model theory, tactics
  • Frédéric Dupuis (@dupuisf): linear algebra, functional analysis
  • Gabriel Ebner (@gebner): tactics, infrastructure, core, formal languages
  • Sébastien Gouëzel (@sgouezel): topology, calculus, geometry, analysis, measure theory
  • Markus Himmel (@TwoFX): category theory
  • Chris Hughes (@ChrisHughes24): algebra
  • Yury G. Kudryashov (@urkud): analysis, topology, measure theory
  • Robert Y. Lewis (@robertylewis): tactics, documentation
  • Heather Macbeth (@hrmacbeth): geometry, analysis
  • Patrick Massot (@patrickmassot): documentation, topology, geometry
  • Bhavik Mehta (@b-mehta): category theory, combinatorics
  • Kyle Miller (@kmill): combinatorics, documentation
  • Scott Morrison (@semorrison): category theory, tactics
  • Oliver Nash (@ocfnash): algebra, geometry, topology
  • Adam Topaz (@adamtopaz): algebra, category theory, algebraic geometry
  • Eric Wieser (@eric-wieser): algebra, infrastructure

Emeritus maintainers:

  • Jeremy Avigad (@avigad): analysis
  • Johannes Hölzl (@johoelzl): measure theory, topology
  • Simon Hudon (@cipher1024): tactics