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Wyszukujesz frazę "asymptotics" wg kryterium: Temat


Tytuł:
Long-time asymptotics for the nonlinear heat equation with a fractional Laplacian in a ball
Autorzy:
Varlamov, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/1206006.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
first initial-boundary value problem
nonlinear heat equation
construction of solutions
higher-order long-time asymptotics
fractional Laplacian
Opis:
The nonlinear heat equation with a fractional Laplacian $[u_t+(-Δ)^{α/2} u = u^2, 0 < α ≤ 2]$, is considered in a unit ball $B$. Homogeneous boundary conditions and small initial conditions are examined. For 3/2 + ε₁ ≤ α ≤ 2, where ε₁ > 0 is small, the global-in-time mild solution from the space $C⁰([0,∞), H₀^{κ}(B))$ with κ < α - 1/2 is constructed in the form of an eigenfunction expansion series. The uniqueness is proved for 0 < κ < α - 1/2, and the higher-order long-time asymptotics is calculated.
Źródło:
Studia Mathematica; 2000, 142, 1; 71-99
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Heat Equation with a Fractional Laplacian in a Disk
Autorzy:
Varlamov, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/965893.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
nonlinear heat equation
long-time asymptotics
fractional Laplacian
initial-boundary value problem in a disk
Opis:
For the nonlinear heat equation with a fractional Laplacian $u_t + (-Δ)^{α/2} u = u^2$, 1 < α ≤ 2, the first initial-boundary value problem in a disk is considered. Small initial conditions, homogeneous boundary conditions, and periodicity conditions in the angular coordinate are imposed. Existence and uniqueness of a global-in-time solution is proved, and the solution is constructed in the form of a series of eigenfunctions of the Laplace operator in the disk. First-order long-time asymptotics of the solution is obtained.
Źródło:
Colloquium Mathematicum; 1999, 81, 1; 101-122
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Kuramoto-Sivashinsky equation in a disk
Autorzy:
Varlamov, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/1208011.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
first initial-boundary value problem
long-time asymptotics
Kuramoto-Sivashinsky equation
disk
Opis:
We consider the first initial-boundary value problem for the 2-D Kuramoto-Sivashinsky equation in a unit disk with homogeneous boundary conditions, periodicity conditions in the angle, and small initial data. Apart from proving the existence and uniqueness of a global in time solution, we construct it in the form of a series in a small parameter present in the initial conditions. In the stable case we also obtain the uniform in space long-time asymptotic expansion of the constructed solution and its asymptotics with respect to the nonlinearity constant. The method can work for other dissipative parabolic equations with dispersion.
Źródło:
Annales Polonici Mathematici; 2000, 73, 3; 227-256
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for solution of systems of singularly perturbed differential equations with adifferential turning point
Autorzy:
Sobchuk, Valentyn
Zelenska, Iryna
Laptiev, Oleksandr
Powiązania:
https://bibliotekanauki.pl/articles/27311440.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
singular perturbations
asymptotics
Airy-Langer functions
small parameter
turning points
punkt zwrotny
funkcje Airy'ego-Langera
asymptota
perturbacja singularna
parametr niski
Opis:
The dynamic development of science requires constant improvement of approaches to modeling physical processes and phenomena. Practically all scientific problems can be described by systems of differential equations. Many scientific problems are described by systems of differential equations of a special class, which belong to the group of so-called singularly perturbed differential equations. Mathematical models of processes described by such differential equations contain a small parameter near the highest derivatives, and it was the presence of this small factor that led to the creation of a large mathematical theory. The work proposes a developed algorithm for constructing uniform asymptotics of solutions to systems of singularly perturbed differential equations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 3; art. no. e145682
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some maximum multigraphs and edge/vertex distance colourings
Autorzy:
Skupień, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/971931.pdf
Data publikacji:
1995
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
(strong) chromatic index
chromatic number
matching
hypercube
error-correcting code
asymptotics
Opis:
Shannon-Vizing-type problems concerning the upper bound for a distance chromatic index of multigraphs G in terms of the maximum degree Δ(G) are studied. Conjectures generalizing those related to the strong chromatic index are presented. The chromatic d-index and chromatic d-number of paths, cycles, trees and some hypercubes are determined. Among hypercubes, however, the exact order of their growth is found.
Źródło:
Discussiones Mathematicae Graph Theory; 1995, 15, 1; 89-106
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete spectrum of zero order pseudodifferential operators
Autorzy:
Rozenblum, Grigori
Powiązania:
https://bibliotekanauki.pl/articles/29519270.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
pseudodifferential operator
eigenvalue asymptotics
Opis:
We study the rate of convergence of eigenvalues to the endpoints of essential spectrum for zero order pseudodifferential operators on a compact manifold.
Źródło:
Opuscula Mathematica; 2023, 43, 2; 247-268
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eigenvalue asymptotics for potential type operators on lipschitz surfaces of codimension greater than 1
Autorzy:
Rozenblum, G.
Tashchiyan, G.
Powiązania:
https://bibliotekanauki.pl/articles/255865.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
integral operators
potential theory
eigenvalue asymptotics
Opis:
For potential type integral operators on a Lipschitz submanifold the asymptotic formula for eigenvalues is proved. The reasoning is based upon the study of the rate of operator convergence as smooth surfaces approximate the Lipschitz one.
Źródło:
Opuscula Mathematica; 2018, 38, 5; 733-758
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A first-order spectral phase transition in a class of periodically modulated Hermitian Jacobi matrices
Autorzy:
Pchelintseva, I.
Powiązania:
https://bibliotekanauki.pl/articles/255740.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Jacobi matrices
spectral phase transition
absolutely continuous spectrum
pure point spectrum
discrete spectrum
subordinacy theory
asymptotics of generalized eigenvectors
Opis:
We consider self-adjoint unbounded Jacobi matrices with diagonal q(n) = b(n)n and off-diagonal entries λ(n) = n, where b(n) is a 2-periodical sequence of real numbers. The parameter space is decomposed into several separate regions, where the spectrum of the operator is either purely absolutely continuous or discrete. We study the situation where the spectral phase transition occurs, namely the case of b(1)b(2) = 4. The main motive of the paper is the investigation of asymptotics of generalized eigenvectors of the Jacobi matrix. The pure point part of the spectrum is analyzed in detail.
Źródło:
Opuscula Mathematica; 2008, 28, 2; 137-150
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eigenvalue asymptotics for the Sturm-Liouville operator with potential having a strong local negative singularity
Autorzy:
Nursultanov, M.
Rozenblum, G.
Powiązania:
https://bibliotekanauki.pl/articles/255426.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Sturm-Liouville operator
singular potential
asymptotics of eigenvalues
Opis:
We find asymptotic formulas for the eigenvalues of the Sturm-Liouville operator on the finite interval, with potential having a strong negative singularity at one endpoint. This is the case of limit circle in H. Weyl sense. We establish that, unlike the case of an infinite interval, the asymptotics for positive eigenvalues does not depend on the potential and it is the same as in the regular case. The asymptotics of the negative eigenvalues may depend on the potential quite strongly, however there are always asymptotically fewer negative eigenvalues than positive ones. By unknown reasons this type of problems had not been studied previously.
Źródło:
Opuscula Mathematica; 2017, 37, 1; 109-139
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Least empirical risk procedures in statistical inference
Autorzy:
Niemiro, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/1340679.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
least distances
convex minimization
tests of significance
least absolute deviations
asymptotics
Opis:
We consider the empirical risk function $Q_n(α)={1\over n} \sum_{i=1}^n \cdot f(α,Z_i)$ (for iid $Z_i$'s) under the assumption that f(α,z) is convex with respect to α. Asymptotics of the minimum of $Q_n(α)$ is investigated. Tests for linear hypotheses are derived. Our results generalize some of those concerning LAD estimators and related tests.
Źródło:
Applicationes Mathematicae; 1993-1995, 22, 1; 55-67
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the eigenvalues of a 2 x 2 block operator matrix
Autorzy:
Muminov, M. I.
Rasulov, T. H.
Powiązania:
https://bibliotekanauki.pl/articles/254735.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
block operator matrix
Fock space
discrete and essential spectra
Birman-Schwinger principle
Efimov effect
discrete spectrum asymptotics
embedded eigenvalues
Opis:
A 2 x 2 block operator matrix H acting in the direct sum of one- and two-particle subspaces of a Fock space is considered. The existence of infinitely many negative eigenvalues of H22 (the second diagonal entry of H) is proved for the case where both of the associated Friedrichs models have a zero energy resonance. For the number N(z) of eigenvalues of H22 lying below z < 0, the following asymptotics is found [formula]. Under some natural conditions the infiniteness of the number of eigenvalues located respectively inside, in the gap, and below the bottom of the essential spectrum of H is proved.
Źródło:
Opuscula Mathematica; 2015, 35, 3; 371-395
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of eigenvalues of some unbounded self-adjoint discrete Jacobi matrices by eigenvaules of finite submatrices
Autorzy:
Malejki, M.
Powiązania:
https://bibliotekanauki.pl/articles/255561.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
self-adjoint unbounded Jacobi matrix
asymptotics
point spectrum
tridiagonal matrix
eigenvalue
Opis:
We investigate the problem of approximation of eigenvalues of some self-adjoint operator in the Hilbert space l2(N) by eigenvalues of suitably chosen principal finite submatrices of an infinite Jacobi matrix that defines the operator considered. We assume the Jacobi operator is bounded from below with compact resolvent. In our research we estimate the asymptotics (with n → ∞) of the joint error of approximation for the first n eigenvalues and eigenvectors of the operator by the eigenvalues and eigenvectors of the finite submatrix of order n x n. The method applied in our research is based on the Rayleigh-Ritz method and Volkmer's results included in [7]. We extend the method to cover a class of infinite symmetric Jacobi matrices with three diagonals satisfying some polynomial growth estimates.
Źródło:
Opuscula Mathematica; 2007, 27, 1; 37-49
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic behaviour and approximation of eigenvalues for unbounded block Jacobi matrices
Autorzy:
Malejki, M.
Powiązania:
https://bibliotekanauki.pl/articles/255505.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
symmetric unbounded Jacobi matrix
block Jacobi matrix
tridiagonal matrix
point spectrum
eigenvalue
asymptotics
Opis:
The research included in the paper concerns a class of symmetric block Jacobi matrices. The problem of the approximation of eigenvalues for a class of a self-adjoint unbounded operators is considered. We estimate the joint error of approximation for the eigenvalues, numbered from 1 to N, for a Jacobi matrix J by the eigenvalues of the finite submatrix J(n) of order pn x pn, where N = max{k ∈ N : k ≤ rpn} and r ∈ (0, 1) is suitably chosen. We apply this result to obtain the asymptotics of the eigenvalues of J in the case p = 3.
Źródło:
Opuscula Mathematica; 2010, 30, 3; 311-330
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the asymptotics of the difference equation with a proportional delay
Autorzy:
Kundrat, P.
Powiązania:
https://bibliotekanauki.pl/articles/255684.pdf
Data publikacji:
2006
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
asymptotics of difference equations
approximation methods for dynamical systems
Opis:
This paper deals with asymptotic properties of a vector difference equation with delayed argument Δxk = Axk +Bx(λk], 0 < λ < 1, k = 0,1,2,..., where A, B are constant matrices and the term [λk] is the integer part of λk. Our aim is to emphasize some resemblances between the asymptotic behaviour of this delay difference equation and its continuous counterpart.
Źródło:
Opuscula Mathematica; 2006, 26, 3; 499-506
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One boundary value problem including a spectral parameter in all boundary conditions
Autorzy:
Kabataş, Ayşe
Powiązania:
https://bibliotekanauki.pl/articles/29519516.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
boundary value problems
asymptotics
Green’s functions
Opis:
In this paper, asymptotic formulae for solutions and Green’s function of a boundary value problem are investigated when the equation and the boundary conditions contain a spectral parameter.
Źródło:
Opuscula Mathematica; 2023, 43, 5; 651-661
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł

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