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Latent roots of lambda-matrices, Kronecker sums and matricial norms

José S. L. Vitória (1980)

Aplikace matematiky

Kronecker sums and matricial norms are used in order to give a method for determining upper bounds for A where A is a latent root of a lambda-matrix. In particular, upper bounds for z are obtained where z is a zero of a polynomial with complex coefficients. The result is compared with other known bounds for z .

Latent Semantic Indexing using eigenvalue analysis for efficient information retrieval

Cherukuri Kumar, Suripeddi Srinivas (2006)

International Journal of Applied Mathematics and Computer Science

Text retrieval using Latent Semantic Indexing (LSI) with truncated Singular Value Decomposition (SVD) has been intensively studied in recent years. However, the expensive complexity involved in computing truncated SVD constitutes a major drawback of the LSI method. In this paper, we demonstrate how matrix rank approximation can influence the effectiveness of information retrieval systems. Besides, we present an implementation of the LSI method based on an eigenvalue analysis for rank approximation...

Lattice of ℤ-module

Yuichi Futa, Yasunari Shidama (2016)

Formalized Mathematics

In this article, we formalize the definition of lattice of ℤ-module and its properties in the Mizar system [5].We formally prove that scalar products in lattices are bilinear forms over the field of real numbers ℝ. We also formalize the definitions of positive definite and integral lattices and their properties. Lattice of ℤ-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lovász) base reduction algorithm [14], and cryptographic systems with lattices [15] and coding theory [9]....

Le théorème fondamental des invariants pour les groupes finis

Mustapha Rais (1977)

Annales de l'institut Fourier

Soit V un espace vectoriel complexe de dimension finie. Soit G un sous-groupe fini de G L ( V ) . On montre que pour chaque entier p 1 , le corps des fonctions rationnelles invariantes par G sur V p s’obtient en prenant le corps des fractions de l’algèbre engendrée par les polarisées des fonctions polynômes G -invariantes sur V .

Limit distributions of many-particle spectra and q-deformed Gaussian variables

Piotr Śniady (2006)

Banach Center Publications

We find the limit distributions for a spectrum of a system of n particles governed by a k-body interaction. The hamiltonian of this system is modelled by a Gaussian random matrix. We show that the limit distribution is a q-deformed Gaussian distribution with the deformation parameter q depending on the fraction k/√n. The family of q-deformed Gaussian distributions include the Gaussian distribution and the semicircular law; therefore our result is a generalization of the results of Wigner [Wig1,...

Limit points of eigenvalues of (di)graphs

Fu Ji Zhang, Zhibo Chen (2006)

Czechoslovak Mathematical Journal

The study on limit points of eigenvalues of undirected graphs was initiated by A. J. Hoffman in 1972. Now we extend the study to digraphs. We prove: 1. Every real number is a limit point of eigenvalues of graphs. Every complex number is a limit point of eigenvalues of digraphs. 2. For a digraph D , the set of limit points of eigenvalues of iterated subdivision digraphs of D is the unit circle in the complex plane if and only if D has a directed cycle. 3. Every limit point of eigenvalues of a set...

Limit points of eigenvalues of truncated unbounded tridiagonal operators

E.K. Ifantis, C.G. Kokologiannaki, E. Petropoulou (2007)

Open Mathematics

Let T be a self-adjoint tridiagonal operator in a Hilbert space H with the orthonormal basis {e n}n=1∞, σ(T) be the spectrum of T and Λ(T) be the set of all the limit points of eigenvalues of the truncated operator T N. We give sufficient conditions such that the spectrum of T is discrete and σ(T) = Λ(T) and we connect this problem with an old problem in analysis.

Limiting spectral distribution of XX' matrices

Arup Bose, Sreela Gangopadhyay, Arnab Sen (2010)

Annales de l'I.H.P. Probabilités et statistiques

The methods to establish the limiting spectral distribution (LSD) of large dimensional random matrices includes the well-known moment method which invokes the trace formula. Its success has been demonstrated in several types of matrices such as the Wigner matrix and the sample covariance matrix. In a recent article Bryc, Dembo and Jiang [Ann. Probab.34 (2006) 1–38] establish the LSD for random Toeplitz and Hankel matrices using the moment method. They perform the necessary counting of terms in the...

Line graphs: their maximum nullities and zero forcing numbers

Shaun Fallat, Abolghasem Soltani (2016)

Czechoslovak Mathematical Journal

The maximum nullity over a collection of matrices associated with a graph has been attracting the attention of numerous researchers for at least three decades. Along these lines various zero forcing parameters have been devised and utilized for bounding the maximum nullity. The maximum nullity and zero forcing number, and their positive counterparts, for general families of line graphs associated with graphs possessing a variety of specific properties are analysed. Building upon earlier work, where...

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