Chinese Quarterly Journal of Mathematics ›› 2019, Vol. 34 ›› Issue (1): 52-56.doi: 10.13371/j.cnki.chin.q.j.m.2019.01.006

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Some Results on H-cordial Graphs and Semi-H-cordial Graphs

  

  1. Department of Mathematical Science of Yang-en University. Department of Management, Fujian Economy and Trade College
  • Accepted:2018-01-02 Online:2019-03-30 Published:2020-10-06
  • About author:CHEN Li-na(1981-), female, native of Quanzhou, Fujian, M.S.D, engages in graph theory and combinatorial optimization; XIE Yan-tao(1980-), male, native of Pingdingshan, Henan, M.s.D, engages in graph theory and combinatorial optimization.
  • Supported by:
    Supported by the Educational and Scientific Research Program for Middle-aged and Young Teachers of Fujian Province in 2016(JAT160593);

Abstract: I. Cahit calls a graph H-cordial if it is possible to label the edges with the numbers from the set{1,-1} in such a way that, for some k, at each vertex v the sum of the labels on the edges incident with v is either k or-k and the inequalities |v(k)-v(-k)| ≤ 1 and|e(1)-e(-1)| ≤ 1 are also satisfied. A graph G is called to be semi-H-cordial, if there exists a labeling f, such that for each vertex v, |f(v)| ≤ 1, and the inequalities |ef(1)-ef(-1)| ≤ 1 and |vf(1)-vf(-1)| ≤ 1 are also satisfied. An odd-degree(even-degree) graph is a graph that all of the vertex is odd(even) vertex. Three conclusions were proved:(1) An H-cordial graph G is either odd-degree graph or even-degree graph;(2) If G is an odd-degree graph, then G is H-cordial if and only if |E(G)| is even;(3) A graph G is semi-H-cordial if and only if |E(G)| is even and G has no Euler component with odd edges. 

Key words: H-cordial, Odd-degree graph, Semi-H-cordial

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