Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "graph eigenvalues." wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-9 z 9
    Tytuł:
    Spectral study of alliances in graphs
    Autorzy:
    Rodríguez-Velazquez, Juan
    Almira, Jose
    Powiązania:
    https://bibliotekanauki.pl/articles/743723.pdf
    Data publikacji:
    2007
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    defensive alliance
    offensive alliance
    dual alliance
    domination
    spectral radius
    graph eigenvalues.
    Opis:
    In this paper we obtain several tight bounds on different types of alliance numbers of a graph, namely (global) defensive alliance number, global offensive alliance number and global dual alliance number. In particular, we investigate the relationship between the alliance numbers of a graph and its algebraic connectivity, its spectral radius, and its Laplacian spectral radius.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2007, 27, 1; 143-157
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A result related to the largest eigenvalue of a tree
    Autorzy:
    Vijayakumar, Gurusamy
    Powiązania:
    https://bibliotekanauki.pl/articles/743093.pdf
    Data publikacji:
    2008
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    eigenvalues of a graph
    characteristic polynomial
    Opis:
    In this note we prove that {0,1,√2,√3,2} is the set of all real numbers l such that the following holds: every tree having an eigenvalue which is larger than l has a subtree whose largest eigenvalue is l.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2008, 28, 3; 557-561
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Some additions to the theory of star partitions of graphs
    Autorzy:
    Bell, Francis
    Cvetković, Dragos
    Rowlinson, Peter
    Simić, Slobodan
    Powiązania:
    https://bibliotekanauki.pl/articles/744251.pdf
    Data publikacji:
    1999
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    graph
    eigenvalues
    eigenspaces
    star partitions
    Opis:
    This paper contains a number of results in the theory of star partitions of graphs. We illustrate a variety of situations which can arise when the Reconstruction Theorem for graphs is used, considering in particular galaxy graphs - these are graphs in which every star set is independent. We discuss a recursive ordering of graphs based on the Reconstruction Theorem, and point out the significance of galaxy graphs in this connection.
    Źródło:
    Discussiones Mathematicae Graph Theory; 1999, 19, 2; 119-134
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determining Graphs by the Complementary Spectrum
    Autorzy:
    Pinheiro, Lucélia K.
    Souza, Bruna S.
    Trevisan, Vilmar
    Powiązania:
    https://bibliotekanauki.pl/articles/31562123.pdf
    Data publikacji:
    2020-05-01
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    graphs
    complementary eigenvalues
    graph isomorphism
    Opis:
    The complementary spectrum of a connected graph G is the set of the complementary eigenvalues of the adjacency matrix of G. In this note, we discuss the possibility of representing G using this spectrum. On one hand, we give evidence that this spectrum distinguishes more graphs than other standard graph spectra. On the other hand, we show that it is hard to compute the complementary spectrum. In particular, we see that computing the complementary spectrum is equivalent to finding all connected induced subgraphs.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2020, 40, 2; 607-620
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Balancedness and the Least Laplacian Eigenvalue of Some Complex Unit Gain Graphs
    Autorzy:
    Belardo, Francesco
    Brunetti, Maurizio
    Reff, Nathan
    Powiązania:
    https://bibliotekanauki.pl/articles/31540652.pdf
    Data publikacji:
    2020-05-01
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    gain graph
    Laplacian eigenvalues
    balanced graph
    algebraic frustration
    Opis:
    Let \(\mathbb{T}_4 = {±1, ±i}\) be the subgroup of 4-th roots of unity inside \(\mathbb{T}\), the multiplicative group of complex units. A complex unit gain graph \(\Phi\) is a simple graph $Γ = (V(Γ) = {v_1, . . ., v_n}, E(Γ))$ equipped with a map \(\varphi:\overrightarrow{E}(Γ)→\mathbb{T}\) defined on the set of oriented edges such that \(\varphi(v_iv_j) = \varphi(v_jv_i)^{−1}\). The gain graph \(\Phi\) is said to be balanced if for every cycle $C = v_{i_1}v_{i_2} . . . v_{i_k}v_{i_1}$ we have \(\varphi(v_{i_1}v_{i_2})\varphi(v_{i_2}v_{i_3}) . . . \varphi(v_{i_k}v_{i_1}) = 1\). It is known that \(\Phi\) is balanced if and only if the least Laplacian eigenvalue \(\lambda_n(\Phi)\) is 0. Here we show that, if \(\Phi\) is unbalanced and \(\varphi(\Phi) ⊆ \mathbb{T}_4\), the eigenvalue \(\lambda_n(\Phi)\) measures how far is \(\Phi\) from being balanced. More precisely, let \(ν(\Phi)\) (respectively, \(∈(\Phi)\)) be the number of vertices (respectively, edges) to cancel in order to get a balanced gain subgraph. We show that \(\lambda_n(\Phi) ≤ ν(\Phi) ≤ ∈(\Phi)\). We also analyze the case when \(\lambda_n(\Phi) = ν(\Phi)\). In fact, we identify the structural conditions on \(\Phi\) that lead to such equality.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2020, 40, 2; 417-433
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Color energy of a unitary Cayley graph
    Autorzy:
    Adiga, Chandrashekar
    Sampathkumar, E.
    Sriraj, M.A.
    Powiązania:
    https://bibliotekanauki.pl/articles/31231988.pdf
    Data publikacji:
    2014-11-01
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    coloring of a graph
    unitary Cayley graph
    gcd-graph
    color eigenvalues
    color energy
    Opis:
    Let G be a vertex colored graph. The minimum number χ(G) of colors needed for coloring of a graph G is called the chromatic number. Recently, Adiga et al. [1] have introduced the concept of color energy of a graph Ec(G) and computed the color energy of few families of graphs with χ(G) colors. In this paper we derive explicit formulas for the color energies of the unitary Cayley graph Xn, the complement of the colored unitary Cayley graph $\overline{(Xn)c}$ and some gcd-graphs.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2014, 34, 4; 707-721
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On composition of signed graphs
    Autorzy:
    Shahul Hameed, K.
    Germina, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/743222.pdf
    Data publikacji:
    2012
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    signed graph
    eigenvalues
    graph composition
    regular graphs
    net-regular signed graphs
    Opis:
    A graph whose edges are labeled either as positive or negative is called a signed graph. In this article, we extend the notion of composition of (unsigned) graphs (also called lexicographic product) to signed graphs. We employ Kronecker product of matrices to express the adjacency matrix of this product of two signed graphs and hence find its eigenvalues when the second graph under composition is net-regular. A signed graph is said to be net-regular if every vertex has constant net-degree, namely, the difference of the number of positive and negative edges incident with a vertex. We also characterize balance in signed graph composition and have some results on the Laplacian matrices of this product.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2012, 32, 3; 507-516
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Displacement of Eigenvalues When Removing a Twin Vertex
    Autorzy:
    Briffa, Johann A.
    Sciriha, Irene
    Powiązania:
    https://bibliotekanauki.pl/articles/31543314.pdf
    Data publikacji:
    2020-05-01
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    eigenvalues
    perturbations
    duplicate and co-duplicate vertices
    threshold graph
    nested split graph
    Opis:
    Twin vertices of a graph have the same open neighbourhood. If they are not adjacent, then they are called duplicates and contribute the eigenvalue zero to the adjacency matrix. Otherwise they are termed co-duplicates, when they contribute −1 as an eigenvalue of the adjacency matrix. On removing a twin vertex from a graph, the spectrum of the adjacency matrix does not only lose the eigenvalue 0 or −1. The perturbation sends a rippling effect to the spectrum. The simple eigenvalues are displaced. We obtain a closed formula for the characteristic polynomial of a graph with twin vertices in terms of two polynomials associated with the perturbed graph. These are used to obtain estimates of the displacements in the spectrum caused by the perturbation.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2020, 40, 2; 435-450
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Clustering based on eigenvectors of the adjacency matrix
    Autorzy:
    Lucińska, M.
    Wierzchoń, S. T.
    Powiązania:
    https://bibliotekanauki.pl/articles/331178.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    spectral clustering
    adjacency matrix eigenvalues
    adjacency matrix eigenvectors
    graph perturbation theory
    eigengap heuristics
    klastrowanie widmowe
    macierz sąsiedztwa
    teoria grafów
    Opis:
    The paper presents a novel spectral algorithm EVSA (eigenvector structure analysis), which uses eigenvalues and eigenvectors of the adjacency matrix in order to discover clusters. Based on matrix perturbation theory and properties of graph spectra we show that the adjacency matrix can be more suitable for partitioning than other Laplacian matrices. The main problem concerning the use of the adjacency matrix is the selection of the appropriate eigenvectors. We thus propose an approach based on analysis of the adjacency matrix spectrum and eigenvector pairwise correlations. Formulated rules and heuristics allow choosing the right eigenvectors representing clusters, i.e., automatically establishing the number of groups. The algorithm requires only one parameter—the number of nearest neighbors. Unlike many other spectral methods, our solution does not need an additional clustering algorithm for final partitioning. We evaluate the proposed approach using real-world datasets of different sizes. Its performance is competitive to other both standard and new solutions, which require the number of clusters to be given as an input parameter.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2018, 28, 4; 771-786
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies