Results 61 to 70 of about 6,200 (156)

On the spectrum of Robin Laplacian in a planar waveguide [PDF]

Czechoslovak Mathematical Journal, 2018
We consider the Laplace operator in a planar waveguide, i.e., an infinite two-dimensional straight strip of constant width, with particular types of Robin boundary conditions. We study the essential spectrum of the corresponding Laplacian when the boundary coupling function has a limit at infinity.
openaire   +2 more sources

A novel method to construct cospectral graphs based on RT operation [PDF]

AIP Advances
This paper presents a new graph operation, RT(G), which is formed by transforming each vertex and edge of the original graph G into a triangle. We analyze the relationship between the signless Laplacian characteristic polynomials of the graph RT(G) and ...
Xiu-Jian Wang, Xiao-Juan Tang, Jia-Bao Liu   +2 more
doaj   +1 more source

On the Laplacian spectrum of k-symmetric graphs

Discrete Mathematics
For some positive integer $k$, if the finite cyclic group $\mathbb{Z}_k$ can act freely on a graph $G$, then we say that $G$ is $k$-symmetric. In 1985, Faria showed that the multiplicity of Laplacian eigenvalue 1 is greater than or equal to the difference between the number of pendant vertices and the number of quasi-pendant vertices.
Sunyo Moon, Hyungkee Yoo
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Discrete analogue of Fučik spectrum of the Laplacian

Journal of Computational and Applied Mathematics, 1999
The Fučík spectrum of the Laplacian with a Dirichlet boundary condition \((-\Delta u=\alpha u^+-\beta u^-)\) and the discrete analog of the Fučík spectrum for the matrix \(A\) \((M\)-matrices) are considered. This analog has properties similar to those of the continuum.
openaire   +3 more sources

Adjacency spectra and Laplacian integrality of zero divisor graphs over some rings

Kuwait Journal of Science
Let 𝑅 be a commutative ring and let 𝑍∗ (𝑅) denote the set of non-zero zero divisors of 𝑅. The zero divisor graph 𝛤(𝑅) is defined as the simple graph with vertex set 𝑍∗ (𝑅), where two distinct vertices 𝑥, 𝑦 ∈ 𝑍∗ (𝑅) are adjacent if and only if 𝑥𝑦 = 0.
Bilal Ahmad Rather, Parvez Ali, M. Imran, A. Kothepeda   +3 more
doaj   +1 more source

LAPLACIAN SPECTRUM AND ENERGY OF NON-COMMUTING GRAPHS OF FINITE RINGS [PDF]

Journal of Algebraic Systems
We compute spectrum, energy, Laplacian spectrum/ energy and signless Laplacian spectrum/energy of non-commuting graphs of certain finite non-commutative rings. In particular, we consider finite rings $R$ such that $|R| = p^2, p^3, p^4$, $p^5$, $p^2q$ and
Monalisha Sharma, Rajat Nath
doaj   +1 more source

Modified absolute value cumulating spectrum sensing algorithm in cognitive radio

Dianxin kexue, 2017
Absolute value cumulating (AVC) algorithm is a common spectrum sensing method in Laplacian noise (LED) surroundings,however,the ‘spikes or outliers' in Laplacian noise can't be fully smoothed,which results in bad detection performance.Aiming at this ...
Zhiyong HE
doaj   +2 more sources

A New Like Quantity Based on “Estrada Index”

Journal of Inequalities and Applications, 2010
We first define a new Laplacian spectrum based on Estrada index, namely, Laplacian Estrada-like invariant, LEEL, and two new Estrada index-like quantities, denoted by S and EEX, respectively, that are generalized versions of the Estrada index. After that,
A. Dilek Güngör
doaj   +1 more source

The essential spectrum of the Laplacian

, 2012
In this article we prove a generalization of Weyl's criterion for the essential spectrum of a self-adjoint operator on a Hilbert space. We then apply this criterion to the Laplacian on functions over open manifolds and get new results for its essential spectrum.
Charalambous, Nelia, Lu, Zhiqin
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The spectrum of the Laplacian on forms

, 2018
In this article we prove a generalization of Weyl's criterion for the spectrum of a self-adjoint nonnegative operator on a Hilbert space. We will apply this new criterion in combination with Cheeger-Fukaya-Gromov and Cheeger-Colding theory to study the $k$-form essential spectrum over a complete manifold with vanishing curvature at infinity or ...
Charalambous, Nelia, Lu, Zhiqin
openaire   +2 more sources