# Erdős Problem 426

A statement in qed.bot, the register of claims of AI work in mathematics. The register grades the evidence attached to each claim; it never rules on whether a proof is correct.

- Identifier: erdos:426
- Collection: Erdős
- Page: https://qed.bot/s/erdos-426
- Formal record: solved; at its source: disproved (Lean)
- Prize: $25
- Machine-checked: no independent check has verified it
- Fidelity F2: The statement corpus cites this proof against its own statement.
- Source: https://www.erdosproblems.com/426

## AI claims

### Aristotle, 20 Apr 2026

Bradač and Christoph (2024)

- Outcome: full (a supporting task)
- Autonomy A1: Collaborative. A human and a system worked the problem together, or the system played a supporting role.
- Evidence V1: Informal. A public write-up exists and has had community scrutiny.
- Fidelity F2: Declared. The authors record how the formal statement corresponds to the claim — a comparator challenge, an alignment table or written divergences — or a statement corpus cites the proof against its own statement.
- Source: Erdős problems AI wiki, https://github.com/teorth/erdosproblems/wiki/AI-contributions-to-Erd%C5%91s-problems

## Checks

- dependencies unavailable, by qed.bot: error: ComparatorChallenges: package directory not found: /tmp/qed-checks/plby-lean-proofs-68da20b9-src_latest/ComparatorChallenges (https://github.com/plby/lean-proofs/blob/68da20b96673899166e94638f5a7fffeb7231d35/src/latest/ErdosProblems/Erdos426.lean)

## Formal statements

- FormalConjectures/ErdosProblems/426.lean, https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/426.lean

Cite as: qed.bot, "Erdős Problem 426", https://qed.bot/s/erdos-426, as of 30 Sep 2026. The register's data is published under CC BY 4.0: https://creativecommons.org/licenses/by/4.0/