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Induced Ramsey Number


The induced Ramsey number r_(ind)(G,H) of two finite simple graphs is the least number of vertices in a graph F such that every red-blue coloring of the edges of F contains a red induced subgraph isomorphic to G or a blue induced subgraph isomorphic to H. The copy must be induced in the entire host graph F, and all its edges must have the specified color. The host need not be a complete graph. For complete graphs, this reduces to the usual Ramsey number.

The Kohayakawa-Prömel-Rödl conjecture asserts a polynomial bound in the order of H when G is fixed. Zhong et al. (2026) proved r_(ind)(G,H)<=7t^(60k^2) for k=|V(G)|>=2 and t=|V(H)|>=2.


See also

Induced Subgraph, Kohayakawa-Prömel-Rödl Conjecture, Ramsey Number

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References

Zhong, C.; Kashima, M.; and Mao, Y. "A Solution to the Kohayakawa-Prömel-Rödl Conjecture." 20 Oct 2026. https://arxiv.org/abs/2610.27478.

Cite this as:

Weisstein, Eric W. "Induced Ramsey Number." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/InducedRamseyNumber.html

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