In 1989, George R. T. Hendry presented a table of two-color graph Ramsey numbers R(G,H) for all pairs of graphs G and H having five vertices, with the exception of seven cases. Until now, only two of the these open cases were solved. This work eliminates another one by computing R(B_3,K_5) = 20, where B_3 = K_2 + K_3 is the book graph of order 5. In addition, we show that for these parameters there exists a unique up to isomorphism critical graph. The results are based on computer algorithms. Among the four remaining open cases in Hendry's table, the most notable is that of K_5 versus K_5, for which it is known that 43
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Center for Advancing the Study of CyberInfrastructure
A. Babak, S.P. Radziszowski, and K.K. Tse, Computation of the Ramsey Number R(B_3,K_5). Bulletin of the Institute of Combinatorics and its Applications, 41 (2004), 71-76.
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