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Circular Chromatic Numbers of Some Distance Graphs
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作者 殷翔 吴建专 《Journal of Southeast University(English Edition)》 EI CAS 2001年第2期75-77,共3页
The circular chromatic number of a graph is an important parameter of a graph. The distance graph G(Z,D) , with a distance set D , is the infinite graph with vertex set Z={0,±1,±2,...} in which tw... The circular chromatic number of a graph is an important parameter of a graph. The distance graph G(Z,D) , with a distance set D , is the infinite graph with vertex set Z={0,±1,±2,...} in which two vertices x and y are adjacent iff y-x∈D . This paper determines the circular chromatic numbers of two classes of distance graphs G(Z,D m,k,k+1 ) and G(Z,D m,k,k+1,k+2 ). 展开更多
关键词 distance graph fractional chromatic number circular chromatic number
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CIRCULAR CHROMATIC NUMBER AND MYCIELSKI GRAPHS 被引量:2
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作者 刘红美 《Acta Mathematica Scientia》 SCIE CSCD 2006年第2期314-320,共7页
For a general graph G, M(G) denotes its Mycielski graph. This article gives a number of new sufficient conditions for G to have the circular chromatic number xc(M(G)) equals to the chromatic number x(M(G)), ... For a general graph G, M(G) denotes its Mycielski graph. This article gives a number of new sufficient conditions for G to have the circular chromatic number xc(M(G)) equals to the chromatic number x(M(G)), which have improved some best sufficient conditions published up to date. 展开更多
关键词 Circular chromatic number Mycielski graphs chromatic number
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EDGE-FACE CHROMATIC NUMBER OF 2-CONNECTED PLANE GRAPHS WITH HIGH MAXIMUM DEGREE 被引量:1
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作者 张忠辅 王维凡 +2 位作者 李敬文 姚兵 卜月华 《Acta Mathematica Scientia》 SCIE CSCD 2006年第3期477-482,共6页
The edge-face chromatic number Xef (G) of a plane graph G is the least number of colors assigned to the edges and faces such that every adjacent or incident pair of them receives different colors. In this article, t... The edge-face chromatic number Xef (G) of a plane graph G is the least number of colors assigned to the edges and faces such that every adjacent or incident pair of them receives different colors. In this article, the authors prove that every 2-connected plane graph G with △(G)≥|G| - 2≥9 has Xef(G) = △(G). 展开更多
关键词 Plane graph edge-face chromatic number edge chromatic number maximum degree
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Geodetic Number and Geo-Chromatic Number of 2-Cartesian Product of Some Graphs
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作者 Medha Itagi Huilgol B. Divya 《Open Journal of Discrete Mathematics》 2022年第1期1-16,共16页
A set <em>S ⊆ V (G)</em> is called a geodetic set if every vertex of <em>G</em> lies on a shortest <em>u-v</em> path for some <em>u, v ∈ S</em>, the minimum cardinality... A set <em>S ⊆ V (G)</em> is called a geodetic set if every vertex of <em>G</em> lies on a shortest <em>u-v</em> path for some <em>u, v ∈ S</em>, the minimum cardinality among all geodetic sets is called geodetic number and is denoted by <img src="Edit_82259359-0135-4a65-9378-b767f0405b48.png" alt="" />. A set <em>C ⊆ V (G)</em> is called a chromatic set if <em>C</em> contains all vertices of different colors in<em> G</em>, the minimum cardinality among all chromatic sets is called the chromatic number and is denoted by <img src="Edit_d849148d-5778-459b-abbb-ff25b5cd659b.png" alt="" />. A geo-chromatic set<em> S</em><sub><em>c</em></sub><em> ⊆ V (G</em><em>)</em> is both a geodetic set and a chromatic set. The geo-chromatic number <img src="Edit_505e203c-888c-471c-852d-4b9c2dd1a31c.png" alt="" /><em> </em>of<em> G</em> is the minimum cardinality among all geo-chromatic sets of<em> G</em>. In this paper, we determine the geodetic number and the geo-chromatic number of 2-cartesian product of some standard graphs like complete graphs, cycles and paths. 展开更多
关键词 Cartesian Product Grid Graphs Geodetic Set Geodetic number chromatic Set chromatic number Geo-chromatic Set Geo-chromatic number
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The Circular Chromatic Number of Some Special Graphs
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作者 殷翔 陈旭瑾 宋增民 《Journal of Southeast University(English Edition)》 EI CAS 2001年第1期73-75,共3页
The circular chromatic number of a graph is a natural generalization of the chromatic number. Circular chromatic number contains more information about the structure of a graph than chromatic number does. In this pape... The circular chromatic number of a graph is a natural generalization of the chromatic number. Circular chromatic number contains more information about the structure of a graph than chromatic number does. In this paper we obtain the circular chromatic numbers of special graphs such as C t k and C t k-v, and give a simple proof of the circular chromatic number of H m,n . 展开更多
关键词 circular chromatic number graph C t k graph C t k-v graph H m n
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Some results on circular chromatic number of a graph
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作者 吴建专 林文松 《Journal of Southeast University(English Edition)》 EI CAS 2008年第2期253-256,共4页
For two integers k and d with (k, d) = 1 and k≥2d, let G^dk be the graph with vertex set {0,1,…k - 1 } in which ij is an edge if and only if d≤| i -j I|≤k - d. The circular chromatic number χc(G) of a graph... For two integers k and d with (k, d) = 1 and k≥2d, let G^dk be the graph with vertex set {0,1,…k - 1 } in which ij is an edge if and only if d≤| i -j I|≤k - d. The circular chromatic number χc(G) of a graph G is the minimum of k/d for which G admits a homomorphism to G^dk. The relationship between χc( G- v) and χc (G)is investigated. In particular, the circular chromatic number of G^dk - v for any vertex v is determined. Some graphs withx χc(G - v) =χc(G) - 1 for any vertex v and with certain properties are presented. Some lower bounds for the circular chromatic number of a graph are studied, and a necessary and sufficient condition under which the circular chromatic number of a graph attains the lower bound χ- 1 + 1/α is proved, where χ is the chromatic number of G and a is its independence number. 展开更多
关键词 (k d)-coloring r-circular-coloring circular chromatic number Mycielski' s graph
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Total Chromatic Number of the Join of K_(m,n) and C_n
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作者 LI Guang-rong ZHANG Li-min 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第2期264-270,共7页
The total chromatic number xT(G) of a graph G is the minimum number of colors needed to color the elements(vertices and edges) of G such that no adjacent or incident pair of elements receive the same color, G is c... The total chromatic number xT(G) of a graph G is the minimum number of colors needed to color the elements(vertices and edges) of G such that no adjacent or incident pair of elements receive the same color, G is called Type 1 if xT(G) =△(G)+1. In this paper we prove that the join of a complete bipartite graph Km,n and a cycle Cn is of Type 1. 展开更多
关键词 total coloring total chromatic number join graphs CYCLE complete bipartite graph
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ENTIRE CHROMATIC NUMBER AND Δ-MATCHING OF OUTERPLANE GRAPHS
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作者 王维凡 张克民 《Acta Mathematica Scientia》 SCIE CSCD 2005年第4期672-680,共9页
Let G be an outerplane graph with maximum degree A and the entire chromatic number Xvef(G). This paper proves that if △ ≥6, then △+ 1≤Xvef(G)≤△+ 2, and Xvef (G) = △+ 1 if and only if G has a matching M... Let G be an outerplane graph with maximum degree A and the entire chromatic number Xvef(G). This paper proves that if △ ≥6, then △+ 1≤Xvef(G)≤△+ 2, and Xvef (G) = △+ 1 if and only if G has a matching M consisting of some inner edges which covers all its vertices of maximum degree. 展开更多
关键词 Outerplane graph MATCHING entire chromatic number
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CHROMATIC NUMBER OF SQUARE OF MAXIMAL OUTERPLANAR GRAPHS
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作者 Luo Xiaofang 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2007年第2期163-168,共6页
Let x(G^2) denote the chromatic number of the square of a maximal outerplanar graph G and Q denote a maximal outerplanar graph obtained by adding three chords y1 y3, y3y5, y5y1 to a 6-cycle y1y2…y6y1. In this paper... Let x(G^2) denote the chromatic number of the square of a maximal outerplanar graph G and Q denote a maximal outerplanar graph obtained by adding three chords y1 y3, y3y5, y5y1 to a 6-cycle y1y2…y6y1. In this paper, it is proved that △ + 1 ≤ x(G^2) ≤△ + 2, and x(G^2) = A + 2 if and only if G is Q, where A represents the maximum degree of G. 展开更多
关键词 chromatic number maximal outerplanar graph square of graph maximum degree
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The Complete Chromatic Number of Maximal Outerplane Graphs
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作者 王维凡 《Chinese Quarterly Journal of Mathematics》 CSCD 1996年第3期19-23,共5页
Let G be a maximal outerplane graph and X0(G) the complete chromatic number of G. This paper determines exactly X0(G) for △(G)≠5 and proves 6≤X0.(G)≤7 for △(G) = 5, where △(G) is the maximum degree of vertices o... Let G be a maximal outerplane graph and X0(G) the complete chromatic number of G. This paper determines exactly X0(G) for △(G)≠5 and proves 6≤X0.(G)≤7 for △(G) = 5, where △(G) is the maximum degree of vertices of G. 展开更多
关键词 maximal outerplane graph complete chromatic number maximum degree of vertices
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Edge-face Chromatic Number of 2-connected 1-tree with △(G) = 5
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作者 DONGGui-xiang CHENDong-ling XUZhen-yu 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第1期90-94,共5页
Wang Wei-fan[1] proved that the edge-face chromatic number of a 2-connected 1-tree with the maximum degree is not less than 6 is its maximum degree, and he conjectured that it is true when the maximum degree is 5. Thi... Wang Wei-fan[1] proved that the edge-face chromatic number of a 2-connected 1-tree with the maximum degree is not less than 6 is its maximum degree, and he conjectured that it is true when the maximum degree is 5. This paper proves the conjecture. 展开更多
关键词 edge-face chromatic number 1-tree
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On the Chromatic Number of (P5, C5, Cricket)-Free Graphs
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作者 Weilun Xu 《Engineering(科研)》 2022年第3期147-154,共8页
For a graph G, let be the chromatic number of G. It is well-known that holds for any graph G with clique number . For a hereditary graph class , whether there exists a function f such that holds for every has been wid... For a graph G, let be the chromatic number of G. It is well-known that holds for any graph G with clique number . For a hereditary graph class , whether there exists a function f such that holds for every has been widely studied. Moreover, the form of minimum such an f is also concerned. A result of Schiermeyer shows that every -free graph G with clique number has . Chudnovsky and Sivaraman proved that every -free with clique number graph is -colorable. In this paper, for any -free graph G with clique number , we prove that . The main methods in the proof are set partition and induction. 展开更多
关键词 P5-Free Graphs chromatic number X-Boundedness
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The Chromatic Number of(P_(5),HVN)-free Graphs
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作者 Yian XU 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2024年第4期1098-1110,共13页
Let G be a graph.We useχ(G)andω(G)to denote the chromatic number and clique number of G respectively.A P_(5)is a path on 5 vertices,and an HVN is a K_(4)together with one more vertex which is adjacent to exactly two... Let G be a graph.We useχ(G)andω(G)to denote the chromatic number and clique number of G respectively.A P_(5)is a path on 5 vertices,and an HVN is a K_(4)together with one more vertex which is adjacent to exactly two vertices of K_(4).Combining with some known result,in this paper we show that if G is(P_(5),HVN)-free,thenχ(G)≤max{min{16,ω(G)+3},ω(G)+1}.This upper bound is almost sharp. 展开更多
关键词 P_(5) HVN chromatic number clique number
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Adjacent-Vertex-Distinguishing Total Chromatic Number of P_m×K_n 被引量:16
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作者 陈祥恩 张忠辅 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2006年第3期489-494,共6页
Let G be a simple graph. Let f be a mapping from V(G) U E(G) to {1, 2,..., k}. Let Cf(v) = {f(v)} U {f(vw)|w ∈ V(G),vw ∈ E(G)} for every v ∈ V(G). If f is a k-propertotal-coloring, and if Cf(u) ... Let G be a simple graph. Let f be a mapping from V(G) U E(G) to {1, 2,..., k}. Let Cf(v) = {f(v)} U {f(vw)|w ∈ V(G),vw ∈ E(G)} for every v ∈ V(G). If f is a k-propertotal-coloring, and if Cf(u) ≠ Cf(v) for uv ∈ V(G),uv E E(G), then f is called k-adjacentvertex-distinguishing total coloring of G(k-AVDTC of G for short). Let χat(G) = min{k|G has a k-adjacent-vertex-distinguishing total coloring}. Then χat(G) is called the adjacent-vertex-distinguishing total chromatic number. The adjacent-vertex-distinguishing total chromatic number on the Cartesion product of path Pm and complete graph Kn is obtained. 展开更多
关键词 GRAPH total coloring adjacent-vertex-distinguishing total coloring adjacent-vertex-distinguishing total chromatic number.
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Adjacent Strong Edge Chromatic Number of Series-Parallel Graphs 被引量:1
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作者 王淑栋 庞善臣 许进 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2005年第2期267-278,共12页
In this paper, we will study the adjacent strong edge coloring of series-parallel graphs, and prove that series-parallel graphs of △(G) = 3 and 4 satisfy the conjecture of adjacent strong edge coloring using the doub... In this paper, we will study the adjacent strong edge coloring of series-parallel graphs, and prove that series-parallel graphs of △(G) = 3 and 4 satisfy the conjecture of adjacent strong edge coloring using the double inductions and the method of exchanging colors from the aspect of configuration property. For series-parallel graphs of △(G) ≥ 5, △(G) ≤ x'as(G) ≤ △(G) + 1. Moreover, x'as(G) = △(G) + 1 if and only if it has two adjacent vertices of maximum degree, where △(G) and X'as(G) denote the maximum degree and the adjacent strong edge chromatic number of graph G respectively. 展开更多
关键词 series-parallel graph adjacent strong edge coloring adjacent strong edge chromatic number.
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Some Planar Graphs with Star Chromatic Number Between Three and Four
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作者 李德明 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2001年第4期500-504,共5页
We construct sonic infinite family of planar graphs with star chromatic number, where, partially answering a question of Vince,
关键词 (k d)-coloring star chromatic number planar graph
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An Upper Bound for the Adjacent Vertex Distinguishing Acyclic Edge Chromatic Number of a Graph 被引量:15
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作者 Xin-sheng Liu Ming-qiang An Yang Gao 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2009年第1期137-140,共4页
A proper k-edge coloring of a graph G is called adjacent vertex distinguishing acyclic edge coloring if there is no 2-colored cycle in G and the color set of edges incident to u is not equal to the color set of edges ... A proper k-edge coloring of a graph G is called adjacent vertex distinguishing acyclic edge coloring if there is no 2-colored cycle in G and the color set of edges incident to u is not equal to the color set of edges incident to v, where uv ∈E(G). The adjacent vertex distinguishing acyclic edge chromatic number of G, denoted by χ'αα(G), is the minimal number of colors in an adjacent vertex distinguishing acyclic edge coloring of G. In this paper we prove that if G(V, E) is a graph with no isolated edges, then χ'αα(G)≤32△. 展开更多
关键词 Adjacent strong edge coloring adjacent vertex distinguishing acyclic edge coloring adjacent vertexdistinguishing acyclic edge chromatic number the LovNsz local lemma
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On total chromatic number of planar graphs without 4-cycles 被引量:7
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作者 Min-le SHANGGUAN 《Science China Mathematics》 SCIE 2007年第1期81-86,共6页
Let G be a simple graph with maximum degree Δ(G) and total chromatic number x ve (G). Vizing conjectured that Δ(G) + 1 ? X ve (G) ? δ(G) + 2 (Total Chromatic Conjecture). Even for planar graphs, this conjecture has... Let G be a simple graph with maximum degree Δ(G) and total chromatic number x ve (G). Vizing conjectured that Δ(G) + 1 ? X ve (G) ? δ(G) + 2 (Total Chromatic Conjecture). Even for planar graphs, this conjecture has not been settled yet. The unsettled difficult case for planar graphs is Δ(G) = 6. This paper shows that if G is a simple planar graph with maximum degree 6 and without 4-cycles, then x ve (G) ? 8. Together with the previous results on this topic, this shows that every simple planar graph without 4-cycles satisfies the Total Chromatic Conjecture. 展开更多
关键词 total chromatic number planar graph F 5-subgraph 05C40
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An Upper Bound for the Adjacent Vertex-Distinguishing Total Chromatic Number of a Graph 被引量:17
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作者 LIU Xin Sheng AN Ming Qiang GAO Yang 《Journal of Mathematical Research and Exposition》 CSCD 2009年第2期343-348,共6页
Let G = (V, E) be a simple connected graph, and |V(G)| ≥ 2. Let f be a mapping from V(G) ∪ E(G) to {1,2…, k}. If arbitary uv ∈ E(G),f(u) ≠ f(v),f(u) ≠ f(uv),f(v) ≠ f(uv); arbitary uv, uw... Let G = (V, E) be a simple connected graph, and |V(G)| ≥ 2. Let f be a mapping from V(G) ∪ E(G) to {1,2…, k}. If arbitary uv ∈ E(G),f(u) ≠ f(v),f(u) ≠ f(uv),f(v) ≠ f(uv); arbitary uv, uw ∈ E(G)(v ≠ w), f(uv) ≠ f(uw);arbitary uv ∈ E(G) and u ≠ v, C(u) ≠ C(v), whereC(u)={f(u)}∪{f(uv)|uv∈E(G)}.Then f is called a k-adjacent-vertex-distinguishing-proper-total coloring of the graph G(k-AVDTC of G for short). The number min{k|k-AVDTC of G} is called the adjacent vertex-distinguishing total chromatic number and denoted by χat(G). In this paper we prove that if △(G) is at least a particular constant and δ ≥32√△ln△, then χat(G) ≤ △(G) + 10^26 + 2√△ln△. 展开更多
关键词 total coloring adjacent vertex distinguishing total coloring adjacent vertex distinguishing total chromatic number Lovasz local lemma.
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Vertex Distinguishing Equitable Total Chromatic Number of Join Graph 被引量:5
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作者 Zhi-wen Wang Li-hong Yan Zhong-fuZhang 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2007年第3期433-438,共6页
A vertex distinguishing equitable total coloring of graph G is a proper total coloring of graph G such that any two distinct vertices' coloring sets are not identical and the difference of the elements colored by any... A vertex distinguishing equitable total coloring of graph G is a proper total coloring of graph G such that any two distinct vertices' coloring sets are not identical and the difference of the elements colored by any two colors is not more than 1. In this paper we shall give vertex distinguishing equitable total chromatic number of join graphs Pn VPn, Cn VCn and prove that they satisfy conjecture 3, namely, the chromatic numbers of vertex distinguishing total and vertex distinguishing equitable total are the same for join graphs Pn V Pn and Cn ∨ Cn. 展开更多
关键词 PATH CYCLE join graph vertex distinguishing equitable total chromatic number
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