This is the work in progress port of mathlib to Lean 4.

The mathlib4 docs are generated automatically from the source .lean files.

A guide on how to port a file from mathlib3 to mathlib4 can be found in the wiki. The porting effort is coordinated through zulip, if you want to contribute to the port please come to the mathlib4 stream.

• Make sure Lean is not running, and close all instances of VSCode running Lean processes.

• Get the newest version of elan. If you already have installed a version of Lean, you can run

  elan self update

  If the above command fails, or if you need to install elan, run

  curl https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh -sSf | sh

  If this also fails, follow the instructions under Regular install here.

• To obtain precompiled olean files, run lake exe cache get. (Skipping this step means the next step will be very slow.)

• To build mathlib4 run lake build.

• To build and run all tests, run make.

• You can use lake build Mathlib.Import.Path to build a particular file, e.g. lake build Mathlib.Algebra.Group.Defs.

• If you added a new file, run the following command to update Mathlib.lean

  find Mathlib -name "*.lean" | env LC_ALL=C sort | sed 's/\.lean//;s,/,.,g;s/^/import /' > Mathlib.lean

You can run lake exe cache get to download cached build files that are computed by mathlib4's automated workflow. If tar terminates with an error, it means that you might have ended up with corrupted files. In this case, run lake exe cache get! to overwrite them (get won't try to download the same file again).

Call lake exe cache to see its help menu.

Building HTML documentation locally is straightforward:

lake -Kdoc=on build Mathlib:docs

The HTML files can then be found in build/doc.

If you are a mathlib contributor and want to update dependencies, use lake update -Kdoc=on. This will update the lake-manifest.json file correctly. You will need to make a PR after committing the changes to this file.

Please refer to https://github.com/leanprover-community/mathlib4/wiki/Using-mathlib4-as-a-dependency