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...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 |e_f(1)-e_f(-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.展开更多
A graph is said to be a product cordial graph if there exists a function with each edge assign the label , such that the number of vertices with label 0 and the number of vertices with label 1 differ atmost by 1, and ...A graph is said to be a product cordial graph if there exists a function with each edge assign the label , such that the number of vertices with label 0 and the number of vertices with label 1 differ atmost by 1, and the number of edges with label 0 and the number of edges with label 1 differ by atmost 1. We discuss the product cordial labeling of the graphs obtained by duplication of some graph elements of gear graph. Also, we derive some product cordial graphs obtained by vertex switching operation on gear graph.展开更多
For a graph, a function is called an edge product cordial labeling of G, if the induced vertex labeling function is defined by the product of the labels of the incident edges as such that the number of edges with labe...For a graph, a function is called an edge product cordial labeling of G, if the induced vertex labeling function is defined by the product of the labels of the incident edges as such that the number of edges with label 1 and the number of edges with label 0 differ by at most 1 and the number of vertices with label 1 and the number of vertices with label 0 differ by at most 1. In this paper, we show that the graphs obtained by duplication of a vertex, duplication of a vertex by an edge or duplication of an edge by a vertex in a crown graph are edge product cordial. Moreover, we show that the graph obtained by duplication of each of the vertices of degree three by an edge in a gear graph is edge product cordial. We also show that the graph obtained by duplication of each of the pendent vertices by a new vertex in a helm graph is edge product cordial.展开更多
Diab proved the following graphs are Cordial;Pm K1,n if and only if(m,n) =(1,2);Cm K1,n;Pm Kn;Cm Kn for all m and n except m ≡ 2(mod 4).In this paper,we proved the Cordiality on the union of 3-regular connected graph...Diab proved the following graphs are Cordial;Pm K1,n if and only if(m,n) =(1,2);Cm K1,n;Pm Kn;Cm Kn for all m and n except m ≡ 2(mod 4).In this paper,we proved the Cordiality on the union of 3-regular connected graph K3 and cycle Cm.First we have the Lemma 2,if uv ∈ E(G),G is Cordial,we add 4 vertices x,y,z,w in sequence to the edge uv,obtain a new graph denoted by G*,then G* is still Cordial,by this lemma,we consider four cases on the union of 3-regular connected graph R3,and for every case we distinguish four subcases on the cycle Cm.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">A graph is said to be cordial if it has 0 - 1 labeling which satisfies particular conditions. In this paper, we cons...<div style="text-align:justify;"> <span style="font-family:Verdana;">A graph is said to be cordial if it has 0 - 1 labeling which satisfies particular conditions. In this paper, we construct the corona between paths and second power of fan graphs and explain the necessary and sufficient conditions for this construction to be cordial.</span> </div>展开更多
A digraph is a graph in which each edge has an orientation. A linear directed path, , is a path whose all edges have the same orientation. A linear simple graph is called directed cordial if it admits 0 - 1 labeling t...A digraph is a graph in which each edge has an orientation. A linear directed path, , is a path whose all edges have the same orientation. A linear simple graph is called directed cordial if it admits 0 - 1 labeling that satisfies certain condition. In this paper, we study the cordiality of directed paths??and their second power . Similar studies are done for ?and the join ?. We show that ,? and ?are directed cordial. Sufficient conditions are given to the join?? to be directed cordial.展开更多
In this paper we prove that the complete bipartite graph kmn where m and n are even, join of two cycle graphs cn and cm where n + m ≡ 0 (mod 4), split graph of cn for even “n”, Kn × P2 where n is even are admi...In this paper we prove that the complete bipartite graph kmn where m and n are even, join of two cycle graphs cn and cm where n + m ≡ 0 (mod 4), split graph of cn for even “n”, Kn × P2 where n is even are admits a Zero-M-Cordial labeling. Further we prove that Kn × P2Bn = K1,n × P2 of odd n admits a Zero-M-Cordial labeling.展开更多
In this paper we prove that the split graphs of K1,n and Bn,n are prime cordial graphs. We also show that the square graph of Bn,n is a prime cordial graph while middle graph of Pn is a prime cordial graph for n≥4 . ...In this paper we prove that the split graphs of K1,n and Bn,n are prime cordial graphs. We also show that the square graph of Bn,n is a prime cordial graph while middle graph of Pn is a prime cordial graph for n≥4 . Further we prove that the wheel graph Wn admits prime cordial labeling for n≥8.展开更多
In this paper we prove that the join of two path graphs, two cycle graphs, Ladder graph and the tensor product are H2-cordial labeling. Further we prove that the join of two wheel graphs Wn and Wm, (mod 4) admits a H-...In this paper we prove that the join of two path graphs, two cycle graphs, Ladder graph and the tensor product are H2-cordial labeling. Further we prove that the join of two wheel graphs Wn and Wm, (mod 4) admits a H-cordial labeling.展开更多
We introduce Tribonacci cordial labeling as an extension of Fibonacci cordial labeling, a well-known form of vertex-labelings. A graph that admits Tribonacci cordial labeling is called Tribonacci cordial graph. In thi...We introduce Tribonacci cordial labeling as an extension of Fibonacci cordial labeling, a well-known form of vertex-labelings. A graph that admits Tribonacci cordial labeling is called Tribonacci cordial graph. In this paper we investigate whether some well-known graphs are Tribonacci cordial.展开更多
For a graph having no isolated vertex, a function is called an edge product cordial labeling of graph G, if the induced vertex labeling function defined by the product of labels of incident edges to each vertex is suc...For a graph having no isolated vertex, a function is called an edge product cordial labeling of graph G, if the induced vertex labeling function defined by the product of labels of incident edges to each vertex is such that the number of edges with label 0 and the number of edges with label 1 differ by at most 1 and the number of vertices with label 0 and the number of vertices with label 1 also differ by at most 1. In this paper, we discuss edge product cordial labeling for some cycle related graphs.展开更多
将文献[2](Shee S C,Ho Y S.The Cordiality of One-point Union of n-copies of a Graph.Discrete Math,1993,117:225-243)的结果推广到一般的圈的一点联,即粘连的圈的个数是任意的且每个圈的顶点数也是任意的情况,并给出了此类一点联...将文献[2](Shee S C,Ho Y S.The Cordiality of One-point Union of n-copies of a Graph.Discrete Math,1993,117:225-243)的结果推广到一般的圈的一点联,即粘连的圈的个数是任意的且每个圈的顶点数也是任意的情况,并给出了此类一点联的Cordial性的分析证明.展开更多
利用文献[5](Seoud M,Abdel Maqsoud A E I,Sheehan J.Harmonious Graphs.Util Math,1995,47:225-233.)中的引理1,研究了Pm1×Pn1与Pm2×Pn2的连接和Pm×Pn与Ck的连接的Cordial性,得到当m1,m2,n1,n2≥2时,(Pm1×Pn1)∨(...利用文献[5](Seoud M,Abdel Maqsoud A E I,Sheehan J.Harmonious Graphs.Util Math,1995,47:225-233.)中的引理1,研究了Pm1×Pn1与Pm2×Pn2的连接和Pm×Pn与Ck的连接的Cordial性,得到当m1,m2,n1,n2≥2时,(Pm1×Pn1)∨(Pm2×Pn2)均为Cordial图;当m,n≥2时,(Pm×Pn)∨Ck是Cordial图的充要条件.展开更多
给出了路Pm、圈Cn、扇Fp和轮Wq4种图之间和的Cordial性,所得结果扩展了文献[1](Gallian J A.ADynamic Survey of Graph Labellings of Graphs.Electronic Journal of Combinatorics,2005(5):DS6)的研究工作.
基金Supported by the Educational and Scientific Research Program for Middle-aged and Young Teachers of Fujian Province in 2016(JAT160593)
文摘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 |e_f(1)-e_f(-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.
文摘A graph is said to be a product cordial graph if there exists a function with each edge assign the label , such that the number of vertices with label 0 and the number of vertices with label 1 differ atmost by 1, and the number of edges with label 0 and the number of edges with label 1 differ by atmost 1. We discuss the product cordial labeling of the graphs obtained by duplication of some graph elements of gear graph. Also, we derive some product cordial graphs obtained by vertex switching operation on gear graph.
文摘For a graph, a function is called an edge product cordial labeling of G, if the induced vertex labeling function is defined by the product of the labels of the incident edges as such that the number of edges with label 1 and the number of edges with label 0 differ by at most 1 and the number of vertices with label 1 and the number of vertices with label 0 differ by at most 1. In this paper, we show that the graphs obtained by duplication of a vertex, duplication of a vertex by an edge or duplication of an edge by a vertex in a crown graph are edge product cordial. Moreover, we show that the graph obtained by duplication of each of the vertices of degree three by an edge in a gear graph is edge product cordial. We also show that the graph obtained by duplication of each of the pendent vertices by a new vertex in a helm graph is edge product cordial.
文摘Diab proved the following graphs are Cordial;Pm K1,n if and only if(m,n) =(1,2);Cm K1,n;Pm Kn;Cm Kn for all m and n except m ≡ 2(mod 4).In this paper,we proved the Cordiality on the union of 3-regular connected graph K3 and cycle Cm.First we have the Lemma 2,if uv ∈ E(G),G is Cordial,we add 4 vertices x,y,z,w in sequence to the edge uv,obtain a new graph denoted by G*,then G* is still Cordial,by this lemma,we consider four cases on the union of 3-regular connected graph R3,and for every case we distinguish four subcases on the cycle Cm.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">A graph is said to be cordial if it has 0 - 1 labeling which satisfies particular conditions. In this paper, we construct the corona between paths and second power of fan graphs and explain the necessary and sufficient conditions for this construction to be cordial.</span> </div>
文摘A digraph is a graph in which each edge has an orientation. A linear directed path, , is a path whose all edges have the same orientation. A linear simple graph is called directed cordial if it admits 0 - 1 labeling that satisfies certain condition. In this paper, we study the cordiality of directed paths??and their second power . Similar studies are done for ?and the join ?. We show that ,? and ?are directed cordial. Sufficient conditions are given to the join?? to be directed cordial.
文摘In this paper we prove that the complete bipartite graph kmn where m and n are even, join of two cycle graphs cn and cm where n + m ≡ 0 (mod 4), split graph of cn for even “n”, Kn × P2 where n is even are admits a Zero-M-Cordial labeling. Further we prove that Kn × P2Bn = K1,n × P2 of odd n admits a Zero-M-Cordial labeling.
文摘In this paper we prove that the split graphs of K1,n and Bn,n are prime cordial graphs. We also show that the square graph of Bn,n is a prime cordial graph while middle graph of Pn is a prime cordial graph for n≥4 . Further we prove that the wheel graph Wn admits prime cordial labeling for n≥8.
文摘In this paper we prove that the join of two path graphs, two cycle graphs, Ladder graph and the tensor product are H2-cordial labeling. Further we prove that the join of two wheel graphs Wn and Wm, (mod 4) admits a H-cordial labeling.
文摘We introduce Tribonacci cordial labeling as an extension of Fibonacci cordial labeling, a well-known form of vertex-labelings. A graph that admits Tribonacci cordial labeling is called Tribonacci cordial graph. In this paper we investigate whether some well-known graphs are Tribonacci cordial.
文摘For a graph having no isolated vertex, a function is called an edge product cordial labeling of graph G, if the induced vertex labeling function defined by the product of labels of incident edges to each vertex is such that the number of edges with label 0 and the number of edges with label 1 differ by at most 1 and the number of vertices with label 0 and the number of vertices with label 1 also differ by at most 1. In this paper, we discuss edge product cordial labeling for some cycle related graphs.
文摘将文献[2](Shee S C,Ho Y S.The Cordiality of One-point Union of n-copies of a Graph.Discrete Math,1993,117:225-243)的结果推广到一般的圈的一点联,即粘连的圈的个数是任意的且每个圈的顶点数也是任意的情况,并给出了此类一点联的Cordial性的分析证明.
文摘利用文献[5](Seoud M,Abdel Maqsoud A E I,Sheehan J.Harmonious Graphs.Util Math,1995,47:225-233.)中的引理1,研究了Pm1×Pn1与Pm2×Pn2的连接和Pm×Pn与Ck的连接的Cordial性,得到当m1,m2,n1,n2≥2时,(Pm1×Pn1)∨(Pm2×Pn2)均为Cordial图;当m,n≥2时,(Pm×Pn)∨Ck是Cordial图的充要条件.
文摘给出了路Pm、圈Cn、扇Fp和轮Wq4种图之间和的Cordial性,所得结果扩展了文献[1](Gallian J A.ADynamic Survey of Graph Labellings of Graphs.Electronic Journal of Combinatorics,2005(5):DS6)的研究工作.
