共查询到20条相似文献,搜索用时 15 毫秒
1.
OntheBestApproximationinNon-ArchimedeanNormedLinearSpacesonWeidun(邱维敦)(DepartmentofMathematics,LongyonNormalCollege,Fujian,36... 相似文献
2.
Lei DENG Ming Ge YANG 《数学学报(英文版)》2006,22(6):1809-1818
Some new coincidence theorems involving admissible set-valued mappings are proved in general noncompact topological spaces. As applications, some new minimax inequalities, section theorem, best approximation theorem, existence theorems of weighted Nash equilibria and Pareto equilibria for multiobjective games are given in general topological spaces. 相似文献
3.
J. Bustamante 《Acta Mathematica Hungarica》2014,143(1):208-219
We present upper and lower estimates for the best constant C n such that, if \({f \in W^{n+1}_1}\) [?1, 1], then $$E_n(f)_1 \leqq C_n||\varphi^{n+1}f^{(n+1)}||_1,$$ where \({\varphi(x) =\sqrt{1 - x^2}}\) . For the proof we first find out the polynomials of the best L 1[?1, 1] approximation of some truncated functions. 相似文献
4.
OntheOrderofBestApproximationbyPolynomialsinH■SpacesXingFuchong(邢富冲)(CentralUniversityforNationalities,Beijing,100081)Communi... 相似文献
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6.
Förster Yanik-Pascal Kieburg Mario Kösters Holger 《Journal of Theoretical Probability》2021,34(4):1917-1950
Journal of Theoretical Probability - We study several kinds of polynomial ensembles of derivative type which we propose to call Pólya ensembles. These ensembles are defined on the spaces of... 相似文献
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A. K. Kamal 《分析论及其应用》2016,32(1):20-26
This paper is part Ⅱ of "On Copositive Approximation in Spaces of Continuous Functions". In this paper, the author shows that if Q is any compact subset of real numbers, and M is any finite dimensional strict Chebyshev subspace of C(Q), then for any admissible function f ∈C(Q)\M, the best copositive approximation to f from M is unique. 相似文献
9.
Dominik Schmid 《Numerical Functional Analysis & Optimization》2013,34(7-8):855-882
We consider scattered data approximation problems on SO(3). To this end, we construct a new operator for polynomial approximation on the rotation group. This operator reproduces Wigner-D functions up to a given degree and has uniformly bounded L p -operator norm for all 1 ≤ p ≤ ∞. The operator provides a polynomial approximation with the same approximation degree of the best polynomial approximation. Moreover, the operator together with a Markov type inequality for Wigner-D functions enables us to derive scattered data L p -Marcinkiewicz–Zygmund inequalities for these functions for all 1 ≤ p ≤ ∞. As a major application of such inequalities, we consider the stability of the weighted least squares approximation problem on SO(3). 相似文献
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Zoltán M. Balogh Alexandre Engulatov Lars Hunziker Outi Elina Maasalo 《Potential Analysis》2012,36(2):317-337
We study the connection between the p-Talagrand inequality and the q-logarithmic Sololev inequality for conjugate exponents p ≥ 2, q ≤ 2 in proper geodesic metric spaces. By means of a general Hamilton–Jacobi semigroup we prove that these are equivalent,
and moreover equivalent to the hypercontractivity of the Hamilton–Jacobi semigroup. Our results generalize those of Lott and
Villani. They can be applied to deduce the p-Talagrand inequality in the sub-Riemannian setting of the Heisenberg group. 相似文献
12.
Let X be a Banach space and Φ be an Orlicz function.Denote by LΦ(I,X)the space of X-valued Φ-integrable functions on the unit interval I equipped with the Luxemburg norm.For f1,f2,...,fm ∈ LΦ(I,X),a distance formula disΦ(f1,f2,...,fm,LΦ(I,G))is presented,where G is a close subspace of X.Moreover,some existence and characterization results concerning the best simultaneous approximation of LΦ(I,G)in LΦ(I,X)are given. 相似文献
13.
We provide irreducibility criteria for multivariate polynomials with coefficients in an arbitrary field that extend a classical result of Pólya for polynomials with integer coefficients. In particular, we provide irreducibility conditions for polynomials of the form f(X)(Y ? f 1(X))…(Y ? f n (X)) + g(X), with f, f 1, ?, f n , g univariate polynomials over an arbitrary field. 相似文献
14.
This paper deals with the problem of uniqueness of best L approximationfor continuous functions. In this paper we use a new method to establish akind of characterization theorems and a sufficient condition for unicity spacean n-dimensional subspace of C〔a,b〕, from which every function f in C〔a,b〕has a unique best L approximation. 相似文献
15.
Ukrainian Mathematical Journal - We introduce new characteristics for elements of Hilbert spaces, namely, their generalized moduli of continuity ωφ(x, Lp,V ([0, δ])) and obtain new... 相似文献
16.
ExistenceandUniquenssofBestSimultaneousApproximationLiuRuizhen(刘瑞珍)(HebeiNormalCollege,Shijazhuang)Onthesimultaneousapproximat... 相似文献
17.
We consider weighted inequalities such as Bernstein, Nikolskii, Remez, etc., inequalities under minimal assumptions on the
weights. It turns out that in most cases this mimimal assumption is the doubling condition. Sometimes, however, as for the
Remez and Nikolskii inequalities, one needs the slightly stronger A
∈
fty condition. We shall consider both the trigonometric and the algebraic cases.
August 20, 1997. Date revised: April 19, 1998. Date accepted: May 26, 1998. 相似文献
18.
We discuss Bernstein–Walsh type inequalities for holomorphic polynomials restricted to curves of the form $$\bigl(z,e^{P_{1}(z)},e^{P_{2}(z)},\ldots,e^{P_{d}(z)}\bigr)\in\mathbb{C}^{d+1},$$ where P 1,P 2,…,P d are fixed polynomials on ? (such that the functions z and $e^{P_{k}(z)}$ are algebraically independent). The existence of such inequalities automatically implies the existence of associated Bernstein–Markov inequalities on the derivatives of polynomials restricted to the curve. The d=1 case has been much discussed in the recent literature. However, the d>1 case requires different techniques, and that is the subject of this work. 相似文献
19.
We develop a theory of best simultaneous approximation for closed convex sets in C ?(Q), the space of all real-valued continuous functions on a compact topological space Q endowed with the usual operations and with the norm ‖x‖ = max q?Q |x(q)|. We give necessary and sufficient conditions for the existence of best simultaneous approximation in a conditionally complete Banach lattice X with a strong unit 1 by elements of the hyperplanes. We study best simultaneous approximation by elements of closed convex sets in C ?(Q) and give various characterizations of best simultaneous approximation. 相似文献
20.
F. G. Avkhadiev 《Russian Mathematics (Iz VUZ)》2018,62(8):71-75
On domains of Euclidean spaces we consider inequalities for test functions and their Laplacians. We describe a family of domains having vanishing Rellich constants. For the Euclidean space of dimension 4 we present a new version of the Rellich inequality. In addition, we prove new one-dimensional Rellich-type integral inequalities for linear combinations of test functions and their derivatives of orders one and two. 相似文献