A Ramsey problem of Harary on graphs with prescribed size

نویسندگان

  • Paul Erdös
  • Ralph J. Faudree
  • Cecil C. Rousseau
  • Richard H. Schelp
چکیده

Lower bounds on the Ramsey number r(G, H), as a function of the size of the graphs G and H, are determined. In particular, if H is a graph with n lines, lower bounds for r(H) = r(H, H) and r(K,, H) are calculated in terms of n in the first case and m and n in the second case. For m = 3 an upper bound is also determined. These results partially answer a question raised by Harary about the relationship between Ramsey numbers and the size of graphs.

برای دانلود 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

Restricted size Ramsey number for path of order three versus graph of order five

Let G and H be simple graphs. The Ramsey number r(G,H) for a pair of graphs G and H is the smallest number r such that any red-blue coloring of the edges of Kr contains a red subgraph G or a blue subgraph H . The size Ramsey number r̂(G,H) for a pair of graphs G and H is the smallest number r̂ such that there exists a graph F with size r̂ satisfying the property that any red-blue coloring of the e...

متن کامل

Extremal Ramsey theory for graphs

If G and H are graphs, define the Ramsey number to be the least number p such that if the lines of the complete graph Kp are colored red and blue (say),either the red subgraph contains a copy of G or the blue subgraph contains H. Also set r(G) = r(G,G) ; these are called the diagonal Ramsey numbers. These definitions are taken from Chvátal and Harary [1J ; other terminology will follow Harary [...

متن کامل

Ramsey Theorems for Multiple Copies of Graphs

If G and H are graphs, define the Ramsey number r(G, H) to be the least number p such that if the edges of the complete graph Kp are colored red and blue (say), either the red graph contains G as a subgraph or the blue graph contains H. Let mG denote the union of m disjoint copies of G . The following result is proved : Let G and H have k and I points respectively and have point independence nu...

متن کامل

Nordhaus-Gaddum type results for the Harary index of graphs

The emph{Harary index} $H(G)$ of a connected graph $G$ is defined as $H(G)=sum_{u,vin V(G)}frac{1}{d_G(u,v)}$ where $d_G(u,v)$ is the distance between vertices $u$ and $v$ of $G$. The Steiner distance in a graph, introduced by Chartrand et al. in 1989, is a natural generalization of the concept of classical graph distance. For a connected graph $G$ of order at least $2$ ...

متن کامل

Ramsey Numbers and the Size of Graphs

For two graph H and G, the Ramsey number r(H,G) is the smallest positive integer n such that every red-blue edge coloring of the complete graph Kn on n vertices contains either a red copy of H or a blue copy of G. Motivated by questions of Erdős and Harary, in this note we study how the Ramsey number r(Ks, G) depends on the size of the graph G. For s ≥ 3, we prove that for every G with m edges,...

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

برای دانلود 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

عنوان ژورنال:
  • Discrete Mathematics

دوره 67  شماره 

صفحات  -

تاریخ انتشار 1987