Results 41 to 50 of about 305 (179)
Laplacian Spectral Characterization of Some Unicyclic Graphs
Journal of Applied Mathematics, 2014 Let W(n;q,m1,m2) be the unicyclic graph with n vertices obtained by attaching two paths of lengths m1 and m2 at two adjacent vertices of cycle Cq. Let U(n;q,m1,m2,…,ms) be the unicyclic graph with n vertices obtained by attaching s paths of lengths m1,m2,
Lijun Yu, Hui Wang, Jiang Zhou
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On the nullity of unicyclic graphs
Linear Algebra and its Applications, 2005 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Xuezhong, Tan, Liu, Bolian
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Sharp Lower Bounds of the Sum-Connectivity Index of Unicyclic Graphs
Journal of Mathematics, 2021 The sum-connectivity index of a graph G is defined as the sum of weights 1/du+dv over all edges uv of G, where du and dv are the degrees of the vertices u and v in graph G, respectively.
Maryam Atapour
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New Sharp Extremal Bounds for the Randić Index of Trees With Prescribed Roman Domination Number
Discrete Dynamics in Nature and Society, Volume 2026, Issue 1, 2026.The Randić index is a classical degree‐based topological index that captures branching features of a graph and has broad applications in chemical graph theory and related network models. Roman domination is a defense‐inspired covering concept in which vertices are assigned protective labels so that every unprotected vertex is adjacent to a strongly ...
Waqar Ali +4 more
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Journal of Applied Mathematics, 2012 Let Φ(G,λ)=det(λIn-L(G))=∑k=0n(-1)kck(G)λn-k be the characteristic polynomial of the Laplacian matrix of a graph G of order n. In this paper, we give four transforms on graphs that decrease all Laplacian coefficients ck(G) and investigate a conjecture A.
Xinying Pai, Sanyang Liu
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Trees With a Given Independence Number Maximizing the Randić Index
Journal of Applied Mathematics, Volume 2026, Issue 1, 2026.The Randić index is a classical degree‐based descriptor with strong empirical connections to branching‐sensitive physicochemical properties of chemical compounds. Defined as R(G) = ∑uv ∈ E(G)1/√(d(u)d(v)), for a simple connected graph G, this index has been extensively studied, especially in the context of trees.
Bojana Borovićanin +3 more
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Edge colouring line graphs of unicyclic graphs
Discrete Applied Mathematics, 1992 A characterization of line graphs of unicyclic graphs is established, and it is proved that the line graph \(G\) of a unicyclic graph is in class 1 unless \(G\) is an odd cycle and an optimal edge colouring of the line graph of a unicyclic graph can be computed in time \(O(| E|)\) (note that the chromatic index problem is known to be \(NP\)-complete ...
Leizhen Cai, John A. Ellis
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Inequalities for Distance Signless Laplacian Matrix Under Minimum‐Degree Constraints
Journal of Mathematics, Volume 2026, Issue 1, 2026.For a connected graph G of order n, let D(G) denote its distance matrix and let Tr(G) be the diagonal matrix formed by the vertex transmissions. The distance signless Laplacian of G is defined by DQ = D(G) + Tr(G). The largest eigenvalue of DQ, written as ∂1QG, is referred to as the distance signless Laplacian spectral radius of G.
Mohd Abrar Ul Haq +3 more
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Maximum Value of the ABC Index of the Edge‐Corona Graph of Two Graphs
Journal of Mathematics, Volume 2026, Issue 1, 2026.This paper is concerned with the atom‐bond connectivity index (ABC index), defined as ABCG=∑uv∈EGdu+dv−2/dudv, where E(G) is the edge set of G and du and dv are degrees of vertices u and v, respectively. G1□G2 denotes the edge‐corona graph of G1 and G2.
Haiqin Liu, Yanling Shao, Pramita Mishra
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Maximum Reciprocal Degree Resistance Distance Index of Unicyclic Graphs
Discrete Dynamics in Nature and Society, 2020 The reciprocal degree resistance distance index of a connected graph G is defined as RDRG=∑u,v⊆VGdGu+dGv/rGu,v, where rGu,v is the resistance distance between vertices u and v in G. Let Un denote the set of unicyclic graphs with n vertices.
Gai-Xiang Cai, Xing-Xing Li, Gui-Dong Yu
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