Wrote short post on a thought experiment about understanding Prop's place in Lean's Sort hierarchy: fixpt.de/blog/2026-06...

Did you know that arXiv is exploring to add Typst? The world's largest preprint archive faces unique challenges to keep science open. Join arXiv veteran Norbert Preining and learn what's ahead for arXiv and Typst. www.youtube.com/watch?v=zNZl...

Typst preprints in arXiv: What will it take? | Typst Meetup

YouTube video by Typst

youtube.com

Wow, Gemini-level AI would have been *so useful to learn* when I was starting my PhD. It gives a clearer explanation to the ties between Logical Relations, Parametricity and Abstract Interpretation than I have ever been able to peer from a single source anywhere: gemini.google.com/share/6ef829...

‎Gemini - direct access to Google AI

Created with Gemini

gemini.google.com

Paulette Koronkevich, William J. Bowman One Weird Trick to Untie Landin's Knot https://arxiv.org/abs/2507.21317

GHC will start maintaining an LTS release – blog.haskell.org/ghc-lts-rele... by @andreaspk.bsky.social #Haskell

GHC LTS Releases | The Haskell Programming Language's blog

blog.haskell.org

Haskell is a great language if you follow all the same software engineering practices as in any other language. If you believe that Haskell is fundamental different from other languages, you ignore all the past decades' lessons learned about design and you write unmaintainable shit.

Incredibly grateful to @sigplan.bsky.social and @sigplan-pldi.bsky.social for awarding #LeanLang the Programming Languages Software Award 2025 at #PLDI2025! #LeanProver #FormalMethods #ProgrammingLanguages #Mathematics #SoftwareVerification

This is a really cool new #LeanLang project with some substantial pedagogical value! @teorth.bsky.social has put out a call looking for volunteers to "playtest" the WIP! terrytao.wordpress.com/2025/05/31/a...

A Lean companion to “Analysis I”

Almost 20 years ago, I wrote a textbook in real analysis called “Analysis I”. It was intended to complement the many good available analysis textbooks out there by focusing more on foun…

terrytao.wordpress.com

Terence Tao@teorth.bsky.social · last yr.

I have just launched a "Lean companion" to my textbook "Analysis I": github.com/teorth/estim... . This gives a Lean translation (or paraphrasing) of the various definitions, theorems, and exercises in the textbook into Lean. Further discussion at terrytao.wordpress.com/2025/05/31/a...

📣 TWO EXCITING NEW LEAN LECTURES! Just released: Two Strachey Lectures from @compscioxford.bsky.social featuring Leo de Moura (Chief Architect, Lean FRO) and Kevin Buzzard (Professor, Imperial College). A thread on these must-see talks 🧵👇 #LeanLang #LeanProver

A record increase in atmospheric CO2 according to data released by NOAA gml.noaa.gov/ccgg/trends/..., much higher than projected in the Global Carbon Budget essd.copernicus.org/articles/17/.... This occurred in the presence of an El Niño (red bars, data also from NOAA!). What does this mean? 1/

This is quite fun. “America would be better off if more people worked in manufacturing.” • 80% of Americans agree • 20% disagree “I would be better off if I worked in a factory.” • 25% of Americans agree • 73% disagree • 2% currently work in a factory t.co/ycnHVZ1gT1

Check out these great UX improvements in Lean 4.18! ✅ New gutter decorations for errors/warnings 🔧 "Unsolved goals" markers to guide your proof 🐙 "Goals accomplished!" celebrations ▶️ Try these now in the Lean4 VSCode extension: marketplace.visualstudio.com/items?itemNa... #LeanLang #LeanProver

👩‍💻Lean users: Lean 4.17 adds inlay hints for automatically-inserted implicit parameters: With autoImplicit enabled you’ll see in-editor visual feedback for parameters that Lean has automatically inferred, improving readability and making code less error-prone! #LeanLang #LeanProver #DeveloperTools

Litao Zhou, Yaoda Zhou, Qianyong Wan and Bruno C.D.S. Oliveira present a new core calculus that extends F_≤ (a well known polymorphic calculus with bounded quantification) with isorecursive types, tackling the tricky combination of subtyping, recursive types, and bounded quantification.

Mathlib is a community-built library of mathematics in Lean with nearly 1.8MM lines of code and 190K mathematical theorems! Over 500 contributors have helped drive Mathlib forward at an incredible pace! Learn more at: leanprover-community.github.io/index.html #leanlang #leanprover #community

We're excited to join Bluesky! The Lean FRO develops Lean, an interactive theorem prover and functional programming language advancing mathematics, formal verification, and AI. Follow us for updates on our roadmap and community. #leanlang #leanprover #mathematics #formalverification #ai