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Wyszukujesz frazę "eigenvalue" wg kryterium: Temat


Tytuł:
On the inversion of certain band matrices
Autorzy:
Neuman, E.
Powiązania:
https://bibliotekanauki.pl/articles/748559.pdf
Data publikacji:
1977
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
spline interpolation
matrix invers
eigenvalue problem
Opis:
Inversion of band matrices is the simplest, direct way of computing interpolating splines. On the other hand, when studying the convergence problems, the bounds of related inverse matrices are useful. This paper contains algorithms of inversion, based on LR decomposition, of tri- and five-diagonal matrices appearing in spline fitting problems. (In this case LR decomposition is possible and unique if one of the diagonals is fixed.) For example, inversion of a tri-diagonal matrix of dimension n requires 12n(3n+5) multiplications when the proposed algorithm is used. Some upper and lower bounds for elements of the inverse matrix are also given. Under certain additional assumptions the numerical stability is proved. MR0488663
Źródło:
Mathematica Applicanda; 1977, 5, 9
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of eigenvalues for a class of differential problems on an infinite interval
Autorzy:
Regińska, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/748517.pdf
Data publikacji:
1978
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Spectral theory, Sturm-Liouville, and scattering theory
eigenfunctions, eigenvalues, and expansions
Eigenvalue problems
Teoria spektralna, funkcje własne, wartości własne
Opis:
The author investigates the problem (1) Lu=λu, u(0)=0, u∈L2(0,∞), where L=d2/dt2+a(t)d/dt+b(t) and domL={u∈L2(0,∞):du/dt absolutely continuous, d2u/dt2∈L2(0,∞), u(0)=0}. She proves that under certain conditions it is possible to approximate the spectrum of (1) by means of the spectrum of a suitable problem of the form −u′′+c(t)u=λu, u(0)=0, u′(n)=α(n)u(n).
The author investigates the problem (1) Lu=λu, u(0)=0, u∈L2(0,∞), where L=d2/dt2+a(t)d/dt+b(t) and domL={u∈L2(0,∞):du/dt absolutely continuous, d2u/dt2∈L2(0,∞), u(0)=0}. She proves that under certain conditions it is possible to approximate the spectrum of (1) by means of the spectrum of a suitable problem of the form −u′′+c(t)u=λu, u(0)=0, u′(n)=α(n)u(n).The review of the paper is available at MR0518666.
Źródło:
Mathematica Applicanda; 1978, 6, 13
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of eigenvalues of nonselfadjoint problems on an infinite interval
Autorzy:
Regińska, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/748435.pdf
Data publikacji:
1979
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Linear boundary value problems,Linear equations,Eigenvalue problems
Opis:
W pracy badane są zagadnienia własne Lu=a u. Dowodzi się, iż wartości własne tego zagadnienia są aproksymowane przez wartości własne pewnych zagadnień własnych na przedziałach skończonych.
The author treats the problem of approximation of the eigenvalues of the nonselfadjoint problem Lu=λu, u(0)=0, u∈L2(0,∞), where L=−d2/dt2+p(x), domL={u∈L2(0,∞):du/dt continuous, d2u/dt2∈L2(0,∞), u(0)=0}. The same question for a selfadjoint problem was answered in the author's recent paper.
Źródło:
Mathematica Applicanda; 1979, 7, 14
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some eigenvalue estimates for wavelet related Toeplitz operators
Autorzy:
Nowak, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/967338.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Schrödinger representation
eigenvalue estimates
Toeplitz operators
Opis:
By a straightforward computation we obtain eigenvalue estimates for Toeplitz operators related to the two standard reproducing formulas of the wavelet theory. Our result extends the estimates for Calderón-Toeplitz operators obtained by Rochberg in [R2]. In the first section we recall two standard reproducing formulas of the wavelet theory, we define Toeplitz operators and discuss some of their properties. The second section contains precise statements of our results and their proofs. At the end of the second section we include some comments about the range of applicability of our estimates.
Źródło:
Colloquium Mathematicum; 1993, 65, 1; 149-156
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of the eigenvalue problem for elliptic operator by finite element method with numerical integration
Autorzy:
Lewińska, E.
Powiązania:
https://bibliotekanauki.pl/articles/748226.pdf
Data publikacji:
1994
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Eigenvalue problems
Opis:
.
The author considers the effect of numerical integration in the case of solving a two-dimensional eigenvalue problem for the second-order elliptic differential operator via the finite element method. It is proved that the optimal estimates for eigenfunctions (namely, the estimates of the same order as the optimal estimates for the classical finite element approximation without numerical integration) are valid under the assumption that the precision of the numerical quadrature is the same as that for the corresponding boundary value problem.
Źródło:
Mathematica Applicanda; 1994, 23, 37
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The upper bound of the number of eigenvalues for a class of perturbed Dirichlet forms
Autorzy:
Cupała, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/1289649.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
eigenvalue asymptotics
Dirichlet form
Markov process
Lie group
Opis:
The theory of Markov processes and the analysis on Lie groups are used to study the eigenvalue asymptotics of Dirichlet forms perturbed by scalar potentials.
Źródło:
Studia Mathematica; 1995, 113, 2; 109-125
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence and uniqueness theorems for fourth-order boundary value problems
Autorzy:
Przybycin, Jolanta
Powiązania:
https://bibliotekanauki.pl/articles/1294726.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
eigenvalue
Leray-Schauder degree
Fredholm alternative
Opis:
We establish the existence and uniqueness theorems for a linear and a nonlinear fourth-order boundary value problem. The results obtained generalize the results of Usmani [4] and Yang [5]. The methods used are based, in principle, on [3], [5].
Źródło:
Annales Polonici Mathematici; 1997, 67, 1; 59-64
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytic hypoellipticity for sums of squares of vector fields
Autorzy:
Himonas, A.
Powiązania:
https://bibliotekanauki.pl/articles/1294221.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
analytic hypoellipticity
sum of squares of vector fields
eigenvalue
bracket condition
characteristic set
symplectic
torus
Opis:
We discuss the open problem of analytic hypoellipticity for sums of squares of vector fields, including some recent partial results and a conjecture of Treves.
Źródło:
Annales Polonici Mathematici; 1998, 70, 1; 117-129
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On existence of energy minimizing configurations for mixtures of two imperfectly bonded conductors
Autorzy:
Lipton, R.
Powiązania:
https://bibliotekanauki.pl/articles/206660.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
contact resistance
optimal design
Stekloff eigenvalue
Opis:
We consider a domain filled with a suspension of heat conducting spheres of conductivity sigma[sub p] embedded in a matrix of lesser conductivity sigma[sub m]. It is assumed that there exists a thermal contact resistance at the sphere - matrix interface.The contact resistance is characterized by a scalar Beta, which has dimensions of conductivity per unit lenght. A current flux is prescribed on the domain boundary and we seek the energy minimizing configuration among all suspensions satisfying a reource constraint on the total volume of spheres. We establish the existence of an energy minimizing configuration within the class of polydisperse suspensions of spheres. The optimal suspension depends upon the size of the domain and consists of spheres of radii greater than or equal to R[sub cr] = Beta[...] or no spheres at all. Here R[sub cr] is the ratio between the interfacial resistance and the mismatch between the resistivity of each phase
Źródło:
Control and Cybernetics; 1998, 27, 2; 217-234
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sub-gradient algorithms for computation of extreme eigenvalues of a real symmetric matrix
Autorzy:
Yassine, A.
Powiązania:
https://bibliotekanauki.pl/articles/205834.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
problem wartości własnej
difference of convex functions
eigenvalue problems
Lagrangian duality
non-convex optimization
sub-gradient algorithms
Opis:
The computation of eigenvalues of a matrix is still of importance from both theoretical and practical points of view. This is a significant problem for numerous industrial and scientific situations, notably in dynamics of structures (e.g. Gerardin, 1984), physics (e.g. Rappaz, 1979), chemistry (e.g. Davidson, 1983), economy (e.g. Morishima, 1971; Neumann, 1946), mathematics (e.g. Golub, 1989; Chatelin, 1983, 1984, 1988). The study of eigenvalue problems remains a delicate task, which generally presents numerical difficulties in relation to its sensivity to roundoff errors that may lead to numerical unstabilities, particularly if the eigenvalues are not well separated. In this paper, new subgradient-algorithms for computation of extreme eigenvalues of a symmetric real matrix are presented. Those algorithms are based on stability of Lagrangian duality for non-convex optimization and on duality in the difference of convex functions. Some experimental results which prove the robustness and efficiency of our algorithms are provided.
Źródło:
Control and Cybernetics; 1998, 27, 3; 387-415
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eigenvalue problems with indefinite weight
Autorzy:
Szulkin, Andrzej
Willem, Michel
Powiązania:
https://bibliotekanauki.pl/articles/1217214.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
eigenvalue problem
Laplacian
p-Laplacian
indefinite weight
Opis:
We consider the linear eigenvalue problem -Δu = λV(x)u, $u ∈ D^{1,2}_0(Ω)$, and its nonlinear generalization $-Δ_{p}u = λV(x)|u|^{p-2}u$, $u ∈ D^{1,p}_0(Ω)$. The set Ω need not be bounded, in particular, $Ω = ℝ^N$ is admitted. The weight function V may change sign and may have singular points. We show that there exists a sequence of eigenvalues $λ_n → ∞$.
Źródło:
Studia Mathematica; 1999, 135, 2; 191-201
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiple solutions for nonlinear discontinuous elliptic problems near resonance
Autorzy:
Kourogenis, Nikolaos
Papageorgiou, Nikolaos
Powiązania:
https://bibliotekanauki.pl/articles/965892.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
discontinuous function
generalized directional derivative
critical point
coercive functional
multiple solutions
Clarke subdifferential
Rayleigh quotient
first eigenvalue
p-Laplacian
elliptic inclusion
nonsmooth Palais-Smale condition
Opis:
We consider a quasilinear elliptic eigenvalue problem with a discontinuous right hand side. To be able to have an existence theory, we pass to a multivalued problem (elliptic inclusion). Using a variational approach based on the critical point theory for locally Lipschitz functions, we show that we have at least three nontrivial solutions when $λ → λ_1$ from the left, $λ_1$ being the principal eigenvalue of the p-Laplacian with the Dirichlet boundary conditions.
Źródło:
Colloquium Mathematicum; 1999, 81, 1; 89-99
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the construction of the common optimal market index in the Sharpe model
Autorzy:
Kuryłek, W.
Powiązania:
https://bibliotekanauki.pl/articles/205979.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
regresja liniowa
zastosowanie teorii systemów w ekonomii
investment
linear regression
loss function
market index
maximal eigenvalue
portfolio analysis
principal components
rates of return
Sharpe model
stock markets
Opis:
The purpose of this paper is to determine one factor which represents the whole market behavior on the basis of the rates of return of all equities traded oo this market. In the seminaal Sharpe model the factor is an exogenous varialble which is not determined by the model itself. This paper extends Sharpe's idea, as it assumes that the factor is a linear combination of all the rates of return of all traded equities. To determine this coefiicients of this linear combination we minimize the loss function which expresses the weighted mean square deviation of all rates of return from their predictions, having given the linear combination form of the market index. It is found that the vector of linear coeffcients has to be a nonzero eigenvector associated with the maximal eigenvalue of the appropriately transformed and estimated covariance matrix. The optimal market index for the Warsaw Stock Exchange was compared with the standard index. It occurs that there is only a very small difference between the standard index of this market and the optimal index.
Źródło:
Control and Cybernetics; 1999, 28, 4; 779-787
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Foundations of the theory of open waveguides
Autorzy:
Nosich, A.I.
Powiązania:
https://bibliotekanauki.pl/articles/308738.pdf
Data publikacji:
2000
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
open waveguide theory
eigenvalue problems
Opis:
The theory of electromagnetic wave eigenmodes propagating on open dielectric and metallic waveguides has been reviewed. The main steps of different theoretical approaches to the problem are outlined and discussed. The unsolved problems and also directions of future development are pointed out.
Źródło:
Journal of Telecommunications and Information Technology; 2000, 1-2; 42-45
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elimination of Finite Eigenvalues of the 2d Roesser Model by State Feedbacks
Autorzy:
Kaczorek, T.
Powiązania:
https://bibliotekanauki.pl/articles/908337.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
eliminacja
stan sprzężenia zwrotnego
elimination
finite eigenvalue
state feedback
2D Roesser model
Opis:
A new problem of decreasing the degree of the closed-loop characteristic polynomial of the 2D Roesser model by a suitable choice of state feedbacks is formulated. Sufficient conditions are established under which it is possible to choose state feedbacks such that the non-zero closed-loop characteristic polynomial has degree zero. A procedure for computation of the feedback gain matrices is presented and illustrated by a numerical example.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2001, 11, 2; 369-376
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł

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