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Computation of the Ramsey Number $R(W_5,K_5)$

Discrete Mathematics 2014-05-30 v1

Abstract

We determine the value of the Ramsey number R(W5,K5)R(W_5,K_5) to be 27, where W5=K1+C4W_5 = K_1 + C_4 is the 4-spoked wheel of order 5. This solves one of the four remaining open cases in the tables given in 1989 by George R. T. Hendry, which included the Ramsey numbers R(G,H)R(G,H) for all pairs of graphs GG and HH having five vertices, except seven entries. In addition, we show that there exists a unique up to isomorphism critical Ramsey graph for W5W_5 versus K5K_5. Our results are based on computer algorithms.

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Cite

@article{arxiv.cs/0512044,
  title  = {Computation of the Ramsey Number $R(W_5,K_5)$},
  author = {Joshua Stinehour and Stanisław Radziszowski and Kung-Kuen Tse},
  journal= {arXiv preprint arXiv:cs/0512044},
  year   = {2014}
}

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5 pages