In order to reveal the complex network characteristics and evolution principle of China aviation network,the probability distribution and evolution trace of arithmetic average of edge vertices nearest neighbor average...In order to reveal the complex network characteristics and evolution principle of China aviation network,the probability distribution and evolution trace of arithmetic average of edge vertices nearest neighbor average degree values of China aviation network were studied based on the statistics data of China civil aviation network in 1988,1994,2001,2008 and 2015.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the route between cities as the edge of the network.Based on the statistical data,the arithmetic averages of edge vertices nearest neighbor average degree values of China aviation network in 1988,1994,2001,2008 and 2015 were calculated.Using the probability statistical analysis method,it was found that the arithmetic average of edge vertices nearest neighbor average degree values had the probability distribution of normal function and the position parameters and scale parameters of the probability distribution had linear evolution trace.展开更多
A proper <em>k</em>-edge coloring of a graph <em>G</em> = (<em>V</em>(<em>G</em>), <em>E</em>(<em>G</em>)) is an assignment <em>c</em>...A proper <em>k</em>-edge coloring of a graph <em>G</em> = (<em>V</em>(<em>G</em>), <em>E</em>(<em>G</em>)) is an assignment <em>c</em>: <em>E</em>(<em>G</em>) → {1, 2, …, <em>k</em>} such that no two adjacent edges receive the same color. A neighbor sum distinguishing <em>k</em>-edge coloring of <em>G</em> is a proper <em>k</em>-edge coloring of <em>G</em> such that <img src="Edit_28f0a24c-7d3f-4bdc-b58c-46dfa2add4b4.bmp" alt="" /> for each edge <em>uv</em> ∈ <em>E</em>(<em>G</em>). The neighbor sum distinguishing index of a graph <em>G</em> is the least integer <em>k</em> such that <em>G </em>has such a coloring, denoted by <em>χ’</em><sub>Σ</sub>(<em>G</em>). Let <img src="Edit_7525056f-b99d-4e38-b940-618d16c061e2.bmp" alt="" /> be the maximum average degree of <em>G</em>. In this paper, we prove <em>χ</em>’<sub>Σ</sub>(<em>G</em>) ≤ max{9, Δ(<em>G</em>) +1} for any normal graph <em>G</em> with <img src="Edit_e28e38d5-9b6d-46da-bfce-2aae47cc36f3.bmp" alt="" />. Our approach is based on the discharging method and Combinatorial Nullstellensatz.展开更多
A proper edge-k-coloring of a graph G is a mapping from E(G) to {1, 2,..., k} such that no two adjacent edges receive the same color. A proper edge-k-coloring of G is called neighbor sum distinguishing if for each e...A proper edge-k-coloring of a graph G is a mapping from E(G) to {1, 2,..., k} such that no two adjacent edges receive the same color. A proper edge-k-coloring of G is called neighbor sum distinguishing if for each edge uv ∈ E(G), the sum of colors taken on the edges incident to u is different from the sum of colors taken on the edges incident to v. Let X(G ) denote the smallest value k in such a ' G coloring of G. This parameter makes sense for graphs containing no isolated edges (we call such graphs normal). The maximum average degree mad(G) of G is the maximum of the average degrees of its non-empty subgraphs. In this paper, we prove that if G is a normal subcubic graph with mad(G) 〈 5 then x'(G) ≤ 5. We also prove that if G is a normal subcubic graph with at least two 2-vertices, 6 colors are enough for a neighbor sum distinguishing edge coloring of G, which holds for the list version as well.展开更多
In this paper, we determine the neighbor connectivity κNB of two kinds of Cayley graphs: alter- nating group networks ANn and star graphs Sn; and give the exact values of edge neighbor connectivity λNB of ANn and C...In this paper, we determine the neighbor connectivity κNB of two kinds of Cayley graphs: alter- nating group networks ANn and star graphs Sn; and give the exact values of edge neighbor connectivity λNB of ANn and Cayley graphs generated by transposition trees Fn. Those are κNB(ANn) = n-1, λNB(ANn) = n-2 and κNB(Sn) = λNB(Гn) = n - 1.展开更多
Let Ф : E(G)→ {1, 2,…, k}be an edge coloring of a graph G. A proper edge-k-coloring of G is called neighbor sum distinguishing if ∑eЭu Ф(e)≠∑eЭu Ф(e) for each edge uv∈E(G).The smallest value k for ...Let Ф : E(G)→ {1, 2,…, k}be an edge coloring of a graph G. A proper edge-k-coloring of G is called neighbor sum distinguishing if ∑eЭu Ф(e)≠∑eЭu Ф(e) for each edge uv∈E(G).The smallest value k for which G has such a coloring is denoted by χ'Σ(G) which makes sense for graphs containing no isolated edge(we call such graphs normal). It was conjectured by Flandrin et al. that χ'Σ(G) ≤△(G) + 2 for all normal graphs,except for C5. Let mad(G) = max{(2|E(H)|)/(|V(H)|)|HЭG}be the maximum average degree of G. In this paper,we prove that if G is a normal graph with△(G)≥5 and mad(G) 〈 3-2/(△(G)), then χ'Σ(G)≤△(G) + 1. This improves the previous results and the bound △(G) + 1 is sharp.展开更多
A proper k-edge coloring of a graph G is an assignment of one of k colors to each edge of G such that there are no two edges with the same color incident to a common vertex.Let f(v)denote the sum of colors of the edge...A proper k-edge coloring of a graph G is an assignment of one of k colors to each edge of G such that there are no two edges with the same color incident to a common vertex.Let f(v)denote the sum of colors of the edges incident to v.A k-neighbor sum distinguishing edge coloring of G is a proper k-edge coloring of G such that for each edge uv∈E(G),f(u)≠f(v).Byχ’_∑(G),we denote the smallest value k in such a coloring of G.Let mad(G)denote the maximum average degree of a graph G.In this paper,we prove that every normal graph with mad(G)<10/3 andΔ(G)≥8 admits a(Δ(G)+2)-neighbor sum distinguishing edge coloring.Our approach is based on the Combinatorial Nullstellensatz and discharging method.展开更多
文摘In order to reveal the complex network characteristics and evolution principle of China aviation network,the probability distribution and evolution trace of arithmetic average of edge vertices nearest neighbor average degree values of China aviation network were studied based on the statistics data of China civil aviation network in 1988,1994,2001,2008 and 2015.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the route between cities as the edge of the network.Based on the statistical data,the arithmetic averages of edge vertices nearest neighbor average degree values of China aviation network in 1988,1994,2001,2008 and 2015 were calculated.Using the probability statistical analysis method,it was found that the arithmetic average of edge vertices nearest neighbor average degree values had the probability distribution of normal function and the position parameters and scale parameters of the probability distribution had linear evolution trace.
文摘A proper <em>k</em>-edge coloring of a graph <em>G</em> = (<em>V</em>(<em>G</em>), <em>E</em>(<em>G</em>)) is an assignment <em>c</em>: <em>E</em>(<em>G</em>) → {1, 2, …, <em>k</em>} such that no two adjacent edges receive the same color. A neighbor sum distinguishing <em>k</em>-edge coloring of <em>G</em> is a proper <em>k</em>-edge coloring of <em>G</em> such that <img src="Edit_28f0a24c-7d3f-4bdc-b58c-46dfa2add4b4.bmp" alt="" /> for each edge <em>uv</em> ∈ <em>E</em>(<em>G</em>). The neighbor sum distinguishing index of a graph <em>G</em> is the least integer <em>k</em> such that <em>G </em>has such a coloring, denoted by <em>χ’</em><sub>Σ</sub>(<em>G</em>). Let <img src="Edit_7525056f-b99d-4e38-b940-618d16c061e2.bmp" alt="" /> be the maximum average degree of <em>G</em>. In this paper, we prove <em>χ</em>’<sub>Σ</sub>(<em>G</em>) ≤ max{9, Δ(<em>G</em>) +1} for any normal graph <em>G</em> with <img src="Edit_e28e38d5-9b6d-46da-bfce-2aae47cc36f3.bmp" alt="" />. Our approach is based on the discharging method and Combinatorial Nullstellensatz.
基金Supported by National Natural Science Foundation of China(Grant Nos.11371355,11471193,11271006,11631014)the Foundation for Distinguished Young Scholars of Shandong Province(Grant No.JQ201501)the Fundamental Research Funds of Shandong University and Independent Innovation Foundation of Shandong University(Grant No.IFYT14012)
文摘A proper edge-k-coloring of a graph G is a mapping from E(G) to {1, 2,..., k} such that no two adjacent edges receive the same color. A proper edge-k-coloring of G is called neighbor sum distinguishing if for each edge uv ∈ E(G), the sum of colors taken on the edges incident to u is different from the sum of colors taken on the edges incident to v. Let X(G ) denote the smallest value k in such a ' G coloring of G. This parameter makes sense for graphs containing no isolated edges (we call such graphs normal). The maximum average degree mad(G) of G is the maximum of the average degrees of its non-empty subgraphs. In this paper, we prove that if G is a normal subcubic graph with mad(G) 〈 5 then x'(G) ≤ 5. We also prove that if G is a normal subcubic graph with at least two 2-vertices, 6 colors are enough for a neighbor sum distinguishing edge coloring of G, which holds for the list version as well.
基金Supported by the National Natural Science Foundation of China(No.11371052,11731002,11571035)
文摘In this paper, we determine the neighbor connectivity κNB of two kinds of Cayley graphs: alter- nating group networks ANn and star graphs Sn; and give the exact values of edge neighbor connectivity λNB of ANn and Cayley graphs generated by transposition trees Fn. Those are κNB(ANn) = n-1, λNB(ANn) = n-2 and κNB(Sn) = λNB(Гn) = n - 1.
基金Supported by the National Natural Science Foundation of China(11471193,11631014)the Foundation for Distinguished Young Scholars of Shandong Province(JQ201501)+1 种基金the Fundamental Research Funds of Shandong UniversityIndependent Innovation Foundation of Shandong University(IFYT14012)
文摘Let Ф : E(G)→ {1, 2,…, k}be an edge coloring of a graph G. A proper edge-k-coloring of G is called neighbor sum distinguishing if ∑eЭu Ф(e)≠∑eЭu Ф(e) for each edge uv∈E(G).The smallest value k for which G has such a coloring is denoted by χ'Σ(G) which makes sense for graphs containing no isolated edge(we call such graphs normal). It was conjectured by Flandrin et al. that χ'Σ(G) ≤△(G) + 2 for all normal graphs,except for C5. Let mad(G) = max{(2|E(H)|)/(|V(H)|)|HЭG}be the maximum average degree of G. In this paper,we prove that if G is a normal graph with△(G)≥5 and mad(G) 〈 3-2/(△(G)), then χ'Σ(G)≤△(G) + 1. This improves the previous results and the bound △(G) + 1 is sharp.
基金Supported by the Natural Science Foundation of Shandong Provence(Grant Nos.ZR2018BA010,ZR2016AM01)the National Natural Science Foundation of China(Grant No.11571258)。
文摘A proper k-edge coloring of a graph G is an assignment of one of k colors to each edge of G such that there are no two edges with the same color incident to a common vertex.Let f(v)denote the sum of colors of the edges incident to v.A k-neighbor sum distinguishing edge coloring of G is a proper k-edge coloring of G such that for each edge uv∈E(G),f(u)≠f(v).Byχ’_∑(G),we denote the smallest value k in such a coloring of G.Let mad(G)denote the maximum average degree of a graph G.In this paper,we prove that every normal graph with mad(G)<10/3 andΔ(G)≥8 admits a(Δ(G)+2)-neighbor sum distinguishing edge coloring.Our approach is based on the Combinatorial Nullstellensatz and discharging method.