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SOME THEOREMS OF THE NORDHAUS-GADDUM CLASS
引用本文:WANG Zhijian Department of Mathematics,Suzhou Railway Teachers College,Suzhou 215009,China. SOME THEOREMS OF THE NORDHAUS-GADDUM CLASS[J]. 系统科学与复杂性, 1993, 0(3)
作者姓名:WANG Zhijian Department of Mathematics  Suzhou Railway Teachers College  Suzhou 215009  China
作者单位:WANG Zhijian Department of Mathematics,Suzhou Railway Teachers College,Suzhou 215009,China
摘    要:Let the chromatic number of G, the edge chromatic number of G and thetotal chromatic number of G be denoted by x(G), x_1(G) and x_2(G), respectively. Forany simple graph G of order p and its complement G, the following inequalities of theNordhaus-Gaddum class are obtained:(i)|2p~(1/2)|-ε_1≤x(G)+x_1(G)≤2p-2 and 0≤x(G)·x_1(G)≤(p-1)~2 for p≥2,(ii)|2p~(1/2)|+ε_1≤x(G)+x_2(G)≤2p-1 and 0≤x(G)·x_2(G)≤p(p-1) for p≥3,(iii)p≤x_1(G)+x_2(G)≤2p-1 and 0≤x_1(G)·x_2(G)≤p(p-1) for p≥3,where ε_1=0, if p~(1/2) is an odd integer, 1, otherwise,ε_2=1, if p~(1/2) is an even integer, 0, otherwise,and [x] denotes the ceiling of x. We also show that these bounds are sharp for everypositive integer p.


SOME THEOREMS OF THE NORDHAUS-GADDUM CLASS
WANG Zhijian. SOME THEOREMS OF THE NORDHAUS-GADDUM CLASS[J]. Journal of Systems Science and Complexity, 1993, 0(3)
Authors:WANG Zhijian
Affiliation:WANG Zhijian Department of Mathematics,Suzhou Railway Teachers College,Suzhou 215009,China
Abstract:
Keywords:Complementary graph  chromatic number  edge chromatic number  total chromatic number  theorem of Nordhaus-Gaddum class
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