On ramsey numbers of forests versus nearly complete graphs
โ Scribed by Gary Chartrand; Ronald J. Gould; Albert D. Polimeni
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 269 KB
- Volume
- 4
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
โฆ Synopsis
Abstract
A formula is presented for the ramsey number of any forest of order at least 3 versus any graph G of order n โฅ 4 having clique number n โ 1. In particular, if T is a tree of order m โฅ 3, then r(T, G) = 1 + (m โ 1)(n โ 2).
๐ SIMILAR VOLUMES
It is shown that a graph of order N and average degree d that does not contain the book B m =K 1 +K 1, m as a subgraph has independence number at least Nf (d ), where f (x)t(log xรx) (x ร ). From this result we find that the book-complete graph Ramsey number satisfies r(B m , K n ) mn 2 รlog(nรe). I
The Ramsey numbers M,,, n,P,, ..., n,P,), p > 2, are calculated. ## 1. Introduction One class of generalized Ramsey numbers that are known exactly are those for the graphs nP2 which consist of n disjoint paths of length 2; E. J. Cockayne and the author proved in 111 that d r(nlp2, ..., n d P 2 ) =
Chvatal established that r(T,, K,,) = (m -1 ) ( n -1 ) + 1, where T, , , is an arbitrary tree of order m and K, is the complete graph of order n. This result was extended by Chartrand, Gould, and Polimeni who showed K, could be replaced by a graph with clique number n and order n + 5 provided n 2 3
## Abstract We investigate the asymptotics of the size Ramsey number __รฎ__(__K__~1,__n__~__F__), where __K__~1,__n__~ is the __n__โstar and __F__ is a fixed graph. The author 11 has recently proved that __rฬ__(__K__~1,n~,__F__)=(1+__o__(1))__n__^2^ for any __F__ with chromatic number ฯ(__F__)=3. He