共查询到20条相似文献,搜索用时 15 毫秒
1.
Xin Li 《Advances in Computational Mathematics》1994,2(3):343-355
The objective of this paper is to give an interrelation between Hankel oeprators on the unit disc and Hankel operators on
the half-plane. As an application, the AAK result on the half-plane is established and the rate of best Hankel approximation
on the halfplane is derived.
Research partially supported by the University Research Grants and Fellowship Committee at UNLV. 相似文献
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We prove that there are holomorphic functions in the Hardy space of the unit ball or the bidisc such that the big Hankel operator with symbol is bounded and for any holomorphic function the function cannot be bounded.
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Let ga(t) and gb(t) be two positive, strictly convex and continuously differentiable functions on an interval (a, b) (−∞ a < b ∞), and let {Ln} be a sequence of linear positive operators, each with domain containing 1, t, ga(t), and gb(t). If Ln(ƒ; x) converges to ƒ(x) uniformly on a compact subset of (a, b) for the test functions ƒ(t) = 1, t, ga(t), gb(t), then so does every ƒ ε C(a, b) satisfying ƒ(t) = O(ga(t)) (t → a+) and ƒ(t) = O(gb(t)) (t → b−). We estimate the convergence rate of Lnƒ in terms of the rates for the test functions and the moduli of continuity of ƒ and ƒ′. 相似文献
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A.G. Ramm 《Journal of Mathematical Analysis and Applications》2007,325(1):490-495
Let A be a linear, closed, densely defined unbounded operator in a Hilbert space. Assume that A is not boundedly invertible. If Eq. (1) Au=f is solvable, and ‖fδ−f‖?δ, then the following results are provided: Problem Fδ(u):=‖Au−fδ‖2+α‖u‖2 has a unique global minimizer uα,δ for any fδ, uα,δ=A*−1(AA*+αI)fδ. There is a function α=α(δ), limδ→0α(δ)=0 such that limδ→0‖uα(δ),δ−y‖=0, where y is the unique minimal-norm solution to (1). A priori and a posteriori choices of α(δ) are given. Dynamical Systems Method (DSM) is justified for Eq. (1). 相似文献
6.
V. N. Temlyakov 《Mathematical Notes》1992,51(5):510-517
Translated from Matematicheskie Zametki, Vol. 51, No. 5, pp. 125–134, May, 1992. 相似文献
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Francis Sullivan 《Annali di Matematica Pura ed Applicata》1975,107(1):245-261
Summary Let X be a rotund, reflexive Banach space, M⊆X a closed subspace and PM: X→M the best approximation operator on M. This paper deals with some aspects of the general question of how PM may be constructed out of simpler operators. A class of operators called B-operators, which generalize best approximation
operators, is defined and conditions are given under which PM is the limit of sequences of B-operators. Several examples and applications are also included.
Entrata in Redazione il 20 novembre 1974. 相似文献
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In this paper we study the Hankel convolution operators on the space of even and entire functions and on Schwartz distribution spaces. We characterize the Hankel convolution operators as those ones that commute with Hankel translations and with a Bessel operator. Also we prove that the Hankel convolution operators are hypercyclic and chaotic on the spaces under consideration. 相似文献
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Integral Equations and Operator Theory - 相似文献
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A.G. Ramm 《Journal of Mathematical Analysis and Applications》2002,271(2):542-545
Variational regularization and the method of quasisolutions are justified for unbounded closed operators. 相似文献
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Summary The purpose of this paper is to unify a number of continuity, perturbation, and discretization properties of best approximations in normed linear spaces or in metric or semimetric spaces. It extends work of Aubin and, more specifically, of Daniel.Research supported in part by AEC AT(45-1)-1947 相似文献
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Sergiu Aizicovici Veli-Matti Hokkanen 《Journal of Mathematical Analysis and Applications》2004,292(2):540-557
The solvability of the evolution system v′(t)+B(t)u(t)∋f(t), v(t)∈A(t)u(t), 0<t<T, with the periodic condition v(0)=v(T) is investigated in the case where are bounded, possibly degenerate, subdifferentials and are unbounded subdifferentials. 相似文献
18.
V. A. Ryazhs'ka 《Journal of Mathematical Sciences》1998,90(2):1930-1932
We give generalizations of the joint spectral mapping theorem for certain classes of generally non-closed commuting operators
on different complex Hilbert spaces.
Translated fromMatematichni Metodi ta Fiziko-Mekhanichni Polya, Vol. 40, No. 2, 1997, pp. 33–35. 相似文献
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Optimization Letters - We propose a flexible approach for computing the resolvent of the sum of weakly monotone operators in real Hilbert spaces. This relies on splitting methods where strong... 相似文献
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Ivan Singer 《Mathematische Annalen》1960,140(2):165-168