نتایج جستجو برای: circulant matrix

تعداد نتایج: 365418  

Journal: :Electr. J. Comb. 2016
Luis H. Gallardo

We associate to any given circulant complex matrix C another one E(C) such that E(E(C)) = C∗ the transpose conjugate of C. All circulant Hadamard matrices of order 4 satisfy a condition C4 on their eigenvalues, namely, the absolute value of the sum of all eigenvalues is bounded above by 4. We prove by a “descent” that uses our operator E that the only circulant Hadamard matrices of order n > 4,...

Journal: :CoRR 2017
Kirsten Koolstra Jeroen Van Gemert Peter Börnert Andrew Webb Rob Remis

Purpose: Design of a preconditioner for fast and efficient parallel imaging and compressed sensing reconstructions. Theory: Parallel imaging and compressed sensing reconstructions become time consuming when the problem size or the number of coils is large, due to the large linear system of equations that has to be solved in l1 and l2-norm based reconstruction algorithms. Such linear systems can...

Journal: :J. Comb. Theory, Ser. A 2002
Ka Hin Leung Siu Lun Ma Bernhard Schmidt

In this paper, a new family of relative difference sets with parameters (m, n, k, λ) = ((q − 1)/(q − 1), 4(q− 1), q, q/4) is constructed where q is a 2-power. The construction is based on the technique used in [2]. By a similar method, we also construct some new circulant weighing matrices of order q where q is a 2-power, d is odd and d ≥ 5. Correspondence: S.L. Ma Department of Mathematics Nat...

Journal: :Electronic Notes in Discrete Mathematics 2007
Gabriela Araujo-Pardo Mika Olsen

In this talk we expose the results about infinite families of vertex critical r-dichromatic circulant tournaments for all r ≥ 3. The existence of these infinite families was conjectured by Neumann-Lara [6], who later proved it for all r ≥ 3 and r = 7. Using different methods we find explicit constructions of these infinite families for all r ≥ 3, including the case when r = 7, which complete th...

Journal: :Discrete Mathematics 2010
Gabriela Araujo-Pardo Mika Olsen

In this paper we exhibit infinite families of vertex critical r-dichromatic circulant tournaments for all r ≥ 3. The existence of these infinite families was conjectured by NeumannLara (7), who later proved it for all r ≥ 3 and r 6= 7. Using different methods we find explicit constructions of these infinite families for all r ≥ 3, including the case when r = 7, which complets the proof of the c...

Journal: :Kybernetika 2010
Martin Gavalec Hana Tomásková

Eigenvectors of a max-min matrix characterize stable states of the corresponding discrete-events system. Investigation of the max-min eigenvectors of a given matrix is therefore of a great practical importance. The eigenproblem in max-min algebra has been studied by many authors. Interesting results were found in describing the structure of the eigenspace, and algorithms for computing the maxim...

1997
RADKA TURCAJOVÁ

The recursive algorithm of a (fast) discrete wavelet transform, as well as its generalizations, can be described as repeated applications of block-Toeplitz operators or, in the case of periodized wavelets, multiplications by block circulant matrices. Singular values of a block circulant matrix are the singular values of some matrix trigonometric series evaluated at certain points. The norm of a...

Journal: :Discrete Mathematics 2005
Yuanping Zhang Xuerong Yong Mordecai J. Golin

Kirchhoo's Matrix Tree Theorem permits the calculation of the number of spanning trees in any given graph G through the evaluation of the determinant of an associated matrix. In the case of some special graphs Boesch and Prodinger 9] have shown how to use properties of Chebyshev polyno-mials to evaluate the associated determinants and derive closed formulas for the number of spanning trees of g...

2014
Hannes Helgason Stefanos Kechagias Vladas Pipiras

Circulant matrix embedding is one of the most popular and efficient methods for the exact generation of Gaussian stationary univariate series. Although the idea of circulant matrix embedding has also been used for the generation of Gaussian stationary random fields, there are many practical covariance structures of random fields where classical embedding methods break down. In this work, we pro...

2015
Wutiphol Sintunavarat Yeol Je Cho

In this paper, we gives an upper bound estimation of the spectral norm for matrices A and B such that the entries in the first row of n×n r-circulant matrix A = Circr(a1, a2, . . . , an) and n×n symmetric r-circulant matrix B = SCircr(a1, a2, . . . , an) are ai = Pi or ai = P 2 i or ai = Pi−1 or ai = P 2 i−1, where {Pi}i=0 is Padovan sequence. At the last section, some illustrative numerical ex...

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