This document explains how to get started with Lean and mathlib.
If you get stuck, please come to the chat room to ask for assistance.
If you prefer, you can watch a short video tutorial
We'll need to set up Lean, an editor that knows about Lean, and mathlib
(the standard library).
Rather than installing Lean directly, we'll install a small program called elan
which
automatically provides the correct version of Lean on a per-project basis. This is recommended for
all users.
-
We'll need a terminal, along with some basic prerequisites. Install homebrew, then run
brew install gmp coreutils
in a terminal (gmp
is required bylean
,coreutils
byleanpkg
). -
At a terminal, run the command
curl https://raw.githubusercontent.com/Kha/elan/master/elan-init.sh -sSf | sh
and hit enter when a question is asked.
It is recommended that you re-login, so that your environment knows about
elan
. (Alternatively, typesource $HOME/.elan/env
to update the current terminal.)
At a terminal, run the command
brew install python3
sudo pip3 install mathlibtools
This will install tools that, amongst other things, let you download compiled binaries for mathlib.
There are two editors you can use with Lean, VS Code and emacs. This document describes using VS Code (for emacs, look at https://github.com/leanprover/lean-mode).
- Install VS Code.
- Launch VS Code.
- Click on the extension icon
(or in older versions) in the side bar on the left edge of
the screen (or press ⇧ Shift⌘ CommandX) and search for
leanprover
. - Click "install" (In old versions of VSCode, you might need to click "reload" afterwards)
- Verify Lean is working, for example by saving a file
test.lean
and entering#eval 1+1
. A green line should appear underneath#eval 1+1
, and hovering the mouse over it you should see2
displayed.
Note however that you cannot use mathlib, and in particular any imports,
in the file test.lean
created above.
👉 If you want to use mathlib, you should now read the instructions about creating and working on Lean projects.