Classification of Finite Simple Groups Formalized in Lean

(cfsg.axiommath.ai)

70 points | by pfdietz 2 hours ago

8 comments

  • mlmonkey 2 hours ago
    Out of curiosity: is it possible to take a frontier model and just let it loose on all math textbooks out there, converting each and every proof/theorem/lemma/etc. into Lean? A frontier model should be able to do that, right? And it's a one-time task: do it once and it's there for eternity, available as a library to be used in other proofs.

    Maybe my understanding of Lean is wrong; I'm thinking of it as a programming language but for Math.

    • jonath_laurent 1 hour ago
      Axiom MTS here. What you describe is pretty close to how we formalised this proof, which is scattered across more than 500 articles and books: a swarm of agents was tasked with going through all these sources.

      One challenge is assembling everything into a coherent whole, since the same informal concept can be formalised in slightly different but incompatible ways.

    • aureianimus 21 minutes ago
      Yes and no. With enough compute, probably, but doing this does not necessarily yield a reusable library. See https://xenaproject.wordpress.com/2026/10/16/how-to-formaliz...
    • bananaflag 1 hour ago
      Yes, but thing is, for a lot of basic stuff there are myriad ways in which it is formulated, so humans have to decide which of them goes in the library. Of course you can include two or five or ten equivalent formulations (like textbooks sometimes do) but still, not everything under the sun.

      Probably this will be done in some form in the coming months.

      • thaumasiotes 13 minutes ago
        > Of course you can include two or five or ten equivalent formulations (like textbooks sometimes do) but still, not everything under the sun.

        Note that mathlib currently includes duplicates of many theorems; I believe deduplication is an active goal (if not one seeing much labor right now).

    • tyromaniac 2 hours ago
      Write a few proofs with it and then come back to this
    • QuesnayJr 1 hour ago
      I think people assume that it would end up not being usable by humans without a lot of hand-holding. Though maybe that's wrong, and somebody should try it.
  • sebzim4500 2 hours ago
    This seems like a very good use of auto-formalization, because in the past mathematicians have incorrectly believed that they were finished with the classification only discover a missing class/sporadic group.

    The original proof was a collaboration of ~100 mathematicians, if Tao is correct then we should expect to see more such collaborations in the future like we do in e.g. physics.

    • QuesnayJr 1 hour ago
      They didn't discover a missing sporadic group. The big gap in the proof (the quasithin case) happened because it was covered in a 600-page unpublished manuscript that under further investigation turned out to be incomplete.
  • vatsachak 2 hours ago
    LLM formalization is not as useful as human formalization, but nice to know that the Classification is correct
  • pfdietz 2 hours ago
    The formalization is 43.1M lines of Lean.
    • bwestergard 1 hour ago
      Is that going to be mathematically useful?
      • pfdietz 33 minutes ago
        The proof was of such complexity and length there were lingering doubts. This dispels them.
      • sebzim4500 1 hour ago
        It's nice to know that they didn't miss anything. The natural language proof is 10,000 pages and they have missed groups in the past.
      • curt15 1 hour ago
        More so if Lean uncovers logical errors. Note also there is already an ongoing 2nd generation proof.
  • QuesnayJr 1 hour ago
    I'm surprised they only found one gap. I would have expected multiple (fixable) gaps would have been uncovered, especially since the result was spread over many papers by many different people.
  • pixl97 2 hours ago
    Page has some kind of redirect bug that steals the back button, may want to open it in a new tab to avoid that.
  • v3ai 1 hour ago
    based if true
  • Salparvezml 1 hour ago
    [flagged]