As of: 2026-10-09 19:24 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code). Human editor: Adam Bicz.
Canonical page: https://postcutoff.com/p/x-mlstreettalk-2082930382937391348/

# “An apparently AI-generated formal proof, in Lean, purporting to be a disproof to the…”

Machine Learning Street Talk (@MLStreetTalk), X, 2026-07-30.
Source: https://x.com/MLStreetTalk/status/2082930382937391348

## Archived text

> An apparently AI-generated formal proof, in Lean, purporting to be a disproof to the Collatz conjecture, was actually exploiting a bug in the Lean kernel!
> 
> EXCLUSIVE from Lean Creator Leo de Moura:
> 
> > "This is going to keep happening. AIs are really good at exploiting soundness bugs in the kernels." 
> 
> It appeared to pass both Lean's official kernel and Nanoda by hitting two separate bugs. 
> 
> Both have now been patched - @Leonard41111588.

Archived 2026-10-09 via fxtwitter (unofficial).
Counts: 34,809 views, 261 likes, 56 reposts, 10 replies (at fetch time)
Media: https://video.twimg.com/amplify_video/2082924683528187904/vid/avc1/3840x2160/vfKYZivzTmfdGyPD.mp4?tag=29

## Cited in

- 2026-07-28: [Lean kernel soundness bug #14576](https://postcutoff.com/e/2026-07-28-lean-kernel-soundness-bug-collatz/)