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The notion of goodness for Ramsey numbers was introduced by Burr and Erdos in 1983. For graphs G and H, let G + H be the graph obtained from disjoint G and H by adding all edges between the vertices of G and H. Denote nH by the union of n disjoint copies of H. Let B(n)((k))n = K-k + nK(1), which is called a book. We first obtain that if t >= 1 and k >= 2 are fixed integers and G is a fixed graph, then for all large n, r(K1, t + G, B (k) n) <= (chi(G) + 1)(n + kt 1) + 1. This is sharp for several classes of graphs. Faudree, Rousseau, and Sheehan in 1978 proved that q2 + q + 2 \leq r(C4, B(2) q2 q+1) \leq q2 + q + 4 for prime power q, which implies that B(2) n is not C4good for q2 q + 1 \leq n \leq q2 + q. It is very difficult to determine the exact values for r(C4, B(2) n). Moreover, Nikiforov and Rousseau in 2009 already proved that B(k) n is (K2 + C4)-good for fixed k \geq 2 and large n. In this paper, we obtain that for fixed k >= 2 and large n, r(K1 + C4, B(k) \biggl\{n) = 2(n + 2k 1) if n is even, 2(n + 2k 1) + 1 if n is odd. This implies that B(k) n is not (K1+ C4)-good for each fixed k \geq 2.
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SIAM JOURNAL ON DISCRETE MATHEMATICS
ISSN: 0895-4801
Year: 2021
Issue: 1
Volume: 35
Page: 23-34
0 . 8 6 8
JCR@2021
0 . 9 0 0
JCR@2023
ESI Discipline: ENGINEERING;
ESI HC Threshold:105
JCR Journal Grade:4
CAS Journal Grade:4
Cited Count:
WoS CC Cited Count: 5
SCOPUS Cited Count: 10
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 0
Affiliated Colleges: