Lean community blog (Posts about simproc)

Fantastic Simprocs and How to Write Them

Yaël Dillies, Paul Lezeau — Fri, 27 Feb 2026 11:00:00 GMT

This is the final post in our simproc series. In our first two posts, we gave an informal introduction to the concept of a simproc, and a brief overview of the inner workings of the simp tactic. The aim of this final post is to build on this by demonstrating how Lean users can write their own simprocs.

Simp, made simple.

Yaël Dillies, Paul Lezeau — Tue, 02 Dec 2025 11:00:00 GMT

This is the second blog post in a series of three. In the first blog post, we introduced the notion of a simproc, which can be thought of as a form of "modular" simp lemma. In this sequel, we give a more detailed exposition of the inner workings of the simp tactic in preparation of our third post, where we will see how to write new simprocs.

Simprocs for the Working Mathematician

Yaël Dillies, Paul Lezeau — Mon, 26 May 2025 14:00:00 GMT

Lean v4.6.0 (back in February 2024!) added support for custom simplification procedures, aka simprocs. This blog post is the first in a series of three aimed at explaining what a simproc is, what kind of problems can be solved with simprocs, and what tools we have to write them. Here is the second blog post.