Computation of the Ramsey Number R(W5,K5)

نویسندگان

  • Joshua Stinehour
  • Stanislaw P. Radziszowski
  • Kung-Kuen Tse
چکیده

We determine the value of the Ramsey number R(W5, K5) to be 27, where W5 = K1 + C4 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) for all pairs of graphs G and H having five vertices, except seven entries. In addition, we show that there exists a unique up to isomorphism critical Ramsey graph for W5 versus K5. Our results are based on computer algorithms.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

The Ramsey Number r(K5-P3,K5)

For two given graphs G1 and G2, the Ramsey number r(G1, G2) is the smallest integer n such that for any graph G of order n, either G contains G1 or the complement of G contains G2. Let Km denote a complete graph of order m and Kn −P3 a complete graph of order n without two incident edges. In this paper, we prove that r(K5 − P3,K5) = 25 without help of computer algorithms.

متن کامل

Zarankiewicz Numbers and Bipartite Ramsey Numbers

The Zarankiewicz number z(b; s) is the maximum size of a subgraph of Kb,b which does not contain Ks,s as a subgraph. The two-color bipartite Ramsey number b(s, t) is the smallest integer b such that any coloring of the edges of Kb,b with two colors contains a Ks,s in the rst color or a Kt,t in the second color.In this work, we design and exploit a computational method for bounding and computing...

متن کامل

Ramsey numbers for small graphs versus small disconnected graphs

The Ramsey number r(G,H) is determined for all disconnected (isolatefree) graphs H of order six and all graphs G of order at most five, except the three cases (G,H) ∈ {(K5 − 2K2, 2K3), (K5 − e, 2K3), (K5, 2K3)} where bounds with difference 1 are established. Moreover, general results are obtained for some small disconnected graphs H and any graph G.

متن کامل

Computing the Ramsey Number $R(K_5-P_3,K_5)$

We give a computer-assisted proof of the fact that R(K5 − P3,K5) = 25. This solves one of the three remaining open cases in Hendry’s table, which listed the Ramsey numbers for pairs of graphs on 5 vertices. We find that there exist no (K5−P3,K5)-good graphs containing a K4 on 23 or 24 vertices, where a graph F is (G, H)-good if F does not contain G and the complement of F does not containH. The...

متن کامل

All Ramsey (2K2,C4)−Minimal Graphs

Let F, G and H be non-empty graphs. The notation F → (G,H) means that if any edge of F is colored by red or blue, then either the red subgraph of F con- tains a graph G or the blue subgraph of F contains a graph H. A graph F (without isolated vertices) is called a Ramsey (G,H)−minimal if F → (G,H) and for every e ∈ E(F), (F − e) 9 (G,H). The set of all Ramsey (G,H)−minimal graphs is denoted by ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • CoRR

دوره abs/cs/0512044  شماره 

صفحات  -

تاریخ انتشار 2005