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Written on the Wall II, Graph Conjecture 109

Must every connected graph satisfy the proposed upper bound on its independence number in terms of residue and largest induced-bipartite-subgraph order? The family K2r+1(KrKr)\overline{K}_{2r+1} \vee (K_r \sqcup K_r) violates it for every r3r \ge 3.

Result
Disproved
Status
Resolved
AI contribution
AI-discovered
Method
Construction
Field
Graph invariants
Posed by
Graffiti (Written on the Wall II)
Year posed
1996
Years open
30y
Solved
2026-07-28
Model
GPT-5.6 Sol Max (Codex)
Vendor
OpenAI
Collaborators
Verification
Lean-verified
Publication
Announced
Significance
5 / 100
Disclosed cost
Wikipedia
No dedicated article

What the AI did

The infinite counterexample family was found with GPT-5.6 Sol Max running in Codex; verified in Lean plus independent Python and C++ enumeration.

Verification

Lean-checked disproof in the google-deepmind/formal-conjectures repository, with independent computational enumeration.

Source

google-deepmind/formal-conjectures (WrittenOnTheWallII)

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