48 research outputs found

    General degree distance of graphs

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    We generalize several topological indices and introduce the general degree distance of a connected graph GG. For a,b∈Ra, b \in \mathbb{R}, the general degree distance DDa,b(G)=βˆ‘v∈V(G)[degG(v)]aSGb(v)DD_{a,b} (G) = \sum_{ v \in V(G)} [deg_{G}(v)]^a S^b_{G} (v), where V(G)V(G) is the vertex set of GG, degG(v)deg_G (v) is the degree of a vertex vv, SGb(v)=βˆ‘w∈V(G)βˆ–{v}[dG(v,w)]bS^b_{G} (v) = \sum_{ w \in V(G) \setminus \{ v \} } [d_{G} (v,w) ]^{b} and dG(v,w)d_{G} (v,w) is the distance between vv and ww in GG. We present some sharp bounds on the general degree distance for multipartite graphs and trees of given order, graphs of given order and chromatic number, graphs of given order and vertex connectivity, and graphs of given order and number of pendant vertices

    The Zagreb indices of graphs with a given clique number

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    AbstractFor a (molecular) graph, the first Zagreb index M1 is equal to the sum of squares of the degrees of vertices, and the second Zagreb index M2 is equal to the sum of the products of the degrees of pairs of adjacent vertices. Let Wn,k be the set of connected n-vertex graphs with clique number k. In this work we characterize the graphs from Wn,k with extremal (maximal and minimal) Zagreb indices, and determine the values of corresponding indices

    A Survey on Monochromatic Connections of Graphs

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    The concept of monochromatic connection of graphs was introduced by Caro and Yuster in 2011. Recently, a lot of results have been published about it. In this survey, we attempt to bring together all the results that dealt with it. We begin with an introduction, and then classify the results into the following categories: monochromatic connection coloring of edge-version, monochromatic connection coloring of vertex-version, monochromatic index, monochromatic connection coloring of total-version.Comment: 26 pages, 3 figure
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