AxiomProver produces machine-checked Lean proofs for all 12 Putnam 2025 problems
Result confirmed
The takeaway
Axiom Math’s autonomous Lean 4 prover solved 8 of 12 problems of the 6 Dec 2025 Putnam competition within exam time and the remaining 4 in the following days, all as machine-checked Lean proofs published on GitHub.
Status
- Claim
Result confirmed
- Our reporting
- Medium confidence
- Verification
- Lean-verified
- Importance
- 3 of 5
- Last verified
- 29 September 2026
Your AI and this story
- GPT-6 AstraIn its training data
- Claude Opus 5.5In its training data
- Gemini 4 HydrogenIn its training data
- Grok 4.7In its training data
It happened before the cutoffs of all four assistants, so it can be in their training data.
Key facts
- Putnam 2025 held 6 Dec 2025; 8/12 solved within the exam window, 12/12 after extra time
- Proofs are formal Lean 4 and publicly released
- Axiom says no human scored 12/12, but the 12/12 includes solutions found after the deadline
- Not an official entry; self-reported timing
What happened
Axiom Math ran its prover on the 2025 Putnam problems, producing formal Lean 4 proofs that any Lean installation can check.
Why it matters
Formal verification removes grading disputes like those around informal IMO proofs, and showed formal provers catching up with informal LLMs on hard competition maths.
Sources
2 sources from 2 sites. Numbers match the chips in the text.
2 sources: 2 primary
Primary
- GitHub: AxiomMath/putnam2025 (Lean proofs)github.com, code
- Axiom Math: From seeing why to checking everythingaxiommath.ai, official
Changes
- Filed