Results 41 to 50 of about 1,271 (139)
On distance signless Laplacian spectrum and energy of graphs
Electronic Journal of Graph Theory and Applications, 2018 The distance signless Laplacian spectral radius of a connected graph G is the largest eigenvalue of the distance signless Laplacian matrix of G, defined as DQ(G) = Tr(G) + D(G), where D(G) is the distance matrix of G and Tr(G) is the diagonal ...
Abdollah Alhevaz +2 more
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Some upper bounds for the signless Laplacian spectral radius of digraphs [PDF]
Transactions on Combinatorics, 2019 Let $G=(V(G),E(G))$ be a digraph without loops and multiarcs, where $V(G)=\{v_1,v_2,$ $\ldots,v_n\}$ and $E(G)$ are the vertex set and the arc set of $G$, respectively. Let $d_i^{+}$ be the outdegree of the vertex $v_i$.
Weige Xi, Ligong Wang
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A Note on Some Bounds of the α‐Estrada Index of Graphs
Advances in Mathematical Physics, Volume 2020, Issue 1, 2020., 2020 Let G be a simple graph with n vertices. Let A~αG=αDG+1−αAG, where 0 ≤ α ≤ 1 and A(G) and D(G) denote the adjacency matrix and degree matrix of G, respectively. EEαG=∑i=1neλi is called the α‐Estrada index of G, where λ1, ⋯, λn denote the eigenvalues of A~αG. In this paper, the upper and lower bounds for EEα(G) are given.
Yang Yang +3 more
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On the Second-Largest Reciprocal Distance Signless Laplacian Eigenvalue
Mathematics, 2021 The signless Laplacian reciprocal distance matrix for a simple connected graph G is defined as RQ(G)=diag(RH(G))+RD(G). Here, RD(G) is the Harary matrix (also called reciprocal distance matrix) while diag(RH(G)) represents the diagonal matrix of the ...
Maryam Baghipur +3 more
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Construction for the Sequences of Q‐Borderenergetic Graphs
Mathematical Problems in Engineering, Volume 2020, Issue 1, 2020., 2020 This research intends to construct a signless Laplacian spectrum of the complement of any k‐regular graph G with order n. Through application of the join of two arbitrary graphs, a new class of Q‐borderenergetic graphs is determined with proof. As indicated in the research, with a regular Q‐borderenergetic graph, sequences of regular Q‐borderenergetic ...
Bo Deng +4 more
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Aα‐Spectral Characterizations of Some Joins
Journal of Mathematics, Volume 2020, Issue 1, 2020., 2020 Let G be a graph with n vertices. For every real α ∈ [0,1], write Aα(G) for the matrix Aα(G) = αD(G) + (1 − α)A(G), where A(G) and D(G) denote the adjacency matrix and the degree matrix of G, respectively. The collection of eigenvalues of Aα(G) together with multiplicities are called the Aα‐spectrum of G.
Tingzeng Wu, Tian Zhou, Naihuan Jing
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On graphs with adjacency and signless Laplacian matrices eigenvectors entries in {−1,+1}
Linear Algebra and its Applications, 2021 Let $G$ be a simple graph. In 1986, Herbert Wilf asked what kind of graphs have an eigenvector with entries formed only by $\pm 1$? In this paper, we answer this question for the adjacency, Laplacian and signless Laplacian matrix of a graph. Besides, we generalize the concept of an exact graph to the adjacency and signless Laplacian matrices.
Jorge Alencar, Leonardo de Lima
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Bounds on the α‐Distance Energy and α‐Distance Estrada Index of Graphs
Discrete Dynamics in Nature and Society, Volume 2020, Issue 1, 2020., 2020 Let G be a simple undirected connected graph, then Dα(G) = αTr(G) + (1 − α)D(G) is called the α‐distance matrix of G, where α ∈ [0,1], D(G) is the distance matrix of G, and Tr(G) is the vertex transmission diagonal matrix of G. In this paper, we study some bounds on the α‐distance energy and α‐distance Estrada index of G.
Yang Yang +3 more
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On the Adjacency, Laplacian, and Signless Laplacian Spectrum of Coalescence of Complete Graphs
Journal of Mathematics, 2016 Coalescence as one of the operations on a pair of graphs is significant due to its simple form of chromatic polynomial. The adjacency matrix, Laplacian matrix, and signless Laplacian matrix are common matrices usually considered for discussion under ...
S. R. Jog, Raju Kotambari
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Spectra of Graphs Resulting from Various Graph Operations and Products: a Survey
Special Matrices, 2018 Let G be a graph on n vertices and A(G), L(G), and |L|(G) be the adjacency matrix, Laplacian matrix and signless Laplacian matrix of G, respectively. The paper is essentially a survey of known results about the spectra of the adjacency, Laplacian and ...
Barik S., Kalita D., Pati S., Sahoo G.
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