I also don't think there's been nearly enough time for peer review of what was actually formalized vs what was intended. How many humans out there actually have a deep enough understanding of the background to be able to check the work? I understand that Lean checks the mechanical steps, but if it's building a ladder to some other result entirely, nobody (certainly nobody on HN) will know for some time.

I'm probably wrong, but what's the point of throwing away all skepticism?

Here's a recent example of an AI exploiting a soundness hole in Lean in a paper purporting to have solved the Collatz Conjecture.

https://leodemoura.github.io/blog/2026-8-1-postmortem-for-ke...

There's also a fairly well known incident where the Lean formalization of the Riemann Hypothesis in Mathlib was incorrect.

(integer multiplication, not matrix multiplication, right?)

That is an idealized caricature, and far from the reality. One needs to validate the statement of the theorem and the boundary conditions needed to prove it (definitions, axioms, kernel soundness, etc), a la dependency injection. Mathlib is a common shared platform of vetted truths, but not all proofs restrict themselves to Mathlib AFAIK, and neither is Mathlib perfect -- particularly subtle mismatches in the definitions.

  > All the human needs to verify is that the statement of the theorem is translated correctly from natural language to Lean. That usually covers a very small surface of the Lean code.

https://arxiv.org/html/2610.08144v1#S2

For complex / tedious proofs I can easily see how small details like this can lead to a valid lean proof (or valid "code"), but missing the important details that got lost.

Oh I fully understand how Lean works, how minimal the kernel is etc. I just think that just because "it compiled", we don't actually know that the autoformalization proved all the right stuff along the way. After all, LLMs can produce correct proofs for statements that don't align with the original intended theorem [1]. I just think we should be a bit more skeptical in general before saying these seminal results are fully true. What's the rush?

[1] - https://arxiv.org/abs/2610.08144

How much lean code do you need to read to check if NAvier-Stokes was correctly formalized?

I just think that with the vast amounts of compute involved and the tendency to reward hack, we can't assume the steps towards that formalization are without error until full human understanding of the formalization.

About your second point.

I bet you enjoy when a peer asks you to find the issues in a fully AI generated PR that’s 95% of the way there.

What are you even saying. Mathematics largely happens “commit by commit” as insufferable as that is a way of saying it, via conferences and meetings and prepublications. You’re attributing some bizarre to morality how mathematicians operate. You’re just upset people aren’t playing at your playground enough to your liking.

Also “real mathematicians” aren’t the people who “math belongs to”, you’re a mathematician if you do math, that’s it.

I mean 95% of a proof is not a proof, and the fact that we got 95% of the way there isn't necessarily an indication that we'll ever get there. There's also a big difference between publishing a mostly-done proof as such and publishing a proof as complete only to retract later.

There's a lot to hate about the academic world, but the solution isn't spewing out terabytes of crappy half-baked results.