Written on the Wall II, Graph Conjecture 103
For every connected graph , is , where is the largest induced-bipartite-subgraph order? An -vertex counterexample - a triangle with four leaves on each of two vertices - has against bound .
- Result
- Disproved
- Status
- Resolved
- AI contribution
- AI-discovered
- Method
- Computation
- Field
- Graph invariants
- Posed by
- Graffiti (Written on the Wall II)
- Year posed
- 1996
- Years open
- 30y
- Solved
- 2026-07-22
- Model
- ChatGPT + Codex
- Vendor
- OpenAI
- Collaborators
- —
- Verification
- Lean-verified
- Publication
- Announced
- Significance
- 5 / 100
- Disclosed cost
- —
- Wikipedia
- No dedicated article
What the AI did
The counterexample was found with ChatGPT and Codex and verified in Lean, alongside exhaustive subset enumeration.
Verification
Lean-checked counterexample merged into the google-deepmind/formal-conjectures repository.