Leaning In! 2026

Banner image for Leaning In!: A universal and existential quantifier, leaning to the right, enclosed within a rhombus that also skews to the right

An in-person workshop for the Lean community in & around Europe, Germany, and Berlin

About

Join us for a day of collaboration and learning centered around the Lean programming language & proof assistant. Whether you're using Lean for software verification, mathematical theorems, functional programming, teaching, or language specification—in short, if you're using Lean!—this workshop offers a space to share ideas, learn new techniques, and connect with fellow enthusiasts.

Leaning In! is an in-person event. Talks will be made available afterwards on YouTube.

Details

Date: Thursday, March 12, 2026

Time: 9:00 AM - 5:00 PM

Venue: Spielfeld Digital Hub
Skalitzer Strasse 85/86
10997 Berlin
Germany

Capacity: 40 participants

Call for Submissions

We'd love to have you! If you have something that you'd like to present, just fill out the talk submission form and we'll get back to you.

Program

Doors open

Opening remarks & setup

Verified software development in Lean

Markus Himmel

Over the past year, the Lean FRO has been making a big push towards making Lean a great general-purpose programming language that you can use to develop formally verified production-ready software. In this presentation, I will give an overview over the many recent innovations in Lean that are relevant for software developers, including improvements to the compiler, the standard library, and the verification infrastructure for monadic programs.

Registration

To register for the event, please go here. A ticket costs 75 EUR.

Friendly Policy

The proceedings of Leaning In! will take place under the Racket Friendly Environment Policy, with, of course, the understanding that the Leaning In! organizers, rather than Racket management, are in charge of this event.

Partners

Logo for BOBKonf

Leaning In! pairs well with BOBKonf, which takes places in Berlin the day after Leaning In!

BOB asks: What if we use the best for a change? You'll find BOB to be a pretty Lean-friendly place. See you there!

Sponsors

To help keep costs down, we appreciate any support you can offer. Sponsors will be proudly listed here and called out on-site. To sponsor Leaning In! 2026, just go here.