Postmortem for Lean Kernel Soundness Bug #14576
leodemoura.github.io/blog/2026-8-1-โฆ
Lean
@leanprover
Lean is a dependently-typed programming language and theorem prover.
- Great to see Lean certificates attached to work like this from day one.yes, nonsofic groups exist: this statement is one of many new beautiful results proved by Astra, our next major model. We're releasing 10 such Astra proofs, complete with lean certificates and CoT walkthroughs for each of them. The results are wide-ranging, from von Neumann
- ๐๐ฉ๐ฆ ๐๐ณ๐ฐ๐ฐ๐ง ๐ช๐ฏ ๐ต๐ฉ๐ฆ ๐๐ฐ๐ฅ๐ฆ, @KSHartnett 's book on the development of Lean and Mathlib, is out across the EU this week. For readers picking it up, the two launch panels he moderated are still available to watch: ๐๐ก๐ ๐๐ฎ๐ข๐ฅ๐๐๐ซ๐ฌ, with Leonardo de Moura,
- Excited to share the launch of Tau Ceti, a new library of AI-formalized mathematics in Lean, with human-curated roadmaps and adversarial review against open rubrics. Tau Ceti: github.com/TauCetiProjectโฆ Review rubrics: github.com/TauCetiProjectโฆ Roadmaps: github.com/TauCetiProjectโฆ
- 13 years ago today, the first commit landed in the Lean repository: a handful of C++ files for debugging and exception handling. Since then: 40,000+ commits, 250+ contributors, and four major versions of Lean. Try it live: live.lean-lang.org More on Lean's history in
