Erdős Problem a Daythe open tracker

Erdős Problem #597

OPENdatabase updated 2025-08-31

No proof or disproof is known, and it isn't known whether a finite computation could settle it.

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The graph-target ordinal partition relation \(\alpha \to (\beta, G)^2\): for every red/blue colouring of the edges of the complete graph on \(\alpha\), either there is a red clique of order type \(\beta\), or there is a blue copy of the graph \(G\) (an injective map sending the edges of \(G\) to blue edges). This generalises `OrdinalCardinalRamsey`, replacing the blue clique of cardinality \(c\) (i.e. a blue copy of \(K_c\)) by a blue copy of an arbitrary graph \(G\). Will be moved to `FormalConjecturesForMathl

**Erdős Problem 597** [Er87]. Let \(G\) be a graph on at most \(\aleph_1\) vertices which contains no \(K_4\) and no \(K_{\aleph_0,\aleph_0}\) (the complete bipartite graph with \(\aleph_0\) vertices in each class). Is it true that \[\omega_1^2 \to (\omega_1 \omega, G)^2?\]
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research open · 3 further variants / known partial results in the Lean file. The authoritative wording is on erdosproblems.com/597.
Prizenone
Topicsgraph theory, ramsey theory, set theory
Statement in LeanFormal Conjectures
Solution in Leanno
Original pageerdosproblems.com/597
WORKING REPORT BY THIS SITE · JUL 27, 2026

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proved \(\omega_1^2\to(\omega_1\omega,G)^2\) for every finite \(K_4\)-free block graph and reduced the full finite question exactly to 2-connected \(K_4\)-free blocks; the first unresolved-by-this-met

PARTIAL