Results 61 to 70 of about 828 (207)
A survey and a new class of graceful unicylic graphs
AKCE International Journal of Graphs and Combinatorics, 2020 A graph G admits a graceful labeling if there is a one-to-one map f from the set of vertices of G to such that when an edge xy is assigned the label the resulting set of edge labels is When such a labeling exists, G is called graceful. Rosa showed that a
Max Pambe Biatch’ +2 more
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The k-Metric Dimension of a Unicyclic Graph
, 2021 Given a connected graph G=(V(G),E(G)), a set S⊆V(G) is said to be a k-metric generator for G if any pair of different vertices in V(G) is distinguished by at least k elements of S.
Alejandro Estrada-Moreno
core +1 more source
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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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
wiley +1 more source
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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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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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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The Estrada index of unicyclic graphs
, 2012 The Estrada index of a graph G is defined as EE(G)=∑i=1neλi, where λ1,λ2,…,λn are the eigenvalues of G. We determine the unique unicyclic graph with maximum Estrada index, the unique bipartite unicyclic graph with maximum Estrada index, and the unique ...
Du, Zhibin, Zhou, Bo, Bo Zhou, Zhibin Du
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Contraharmonic Index: Extremal Results for Unicyclic Graphs and Bounds for General Graphs
Journal of Mathematics, Volume 2026, Issue 1, 2026.Let G be a graph with edge set E(G). The degree of a vertex w in G is denoted by dw. The contraharmonic index of G is defined as CHG=∑uv∈EGdu+dv−1du2+dv2. In this paper, we investigate several properties of the contraharmonic index, including extremal results for unicyclic graphs of a given order, as well as bounds and the effects of an edge removal in
Abdulaziz Mutlaq Alotaibi +2 more
wiley +1 more source