共查询到20条相似文献,搜索用时 554 毫秒
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Feng Dai 《Journal of Mathematical Analysis and Applications》2006,315(2):711-724
We study the Kolmogorov m-widths and the linear m-widths of the weighted Besov classes on [−1,1], where Lq,μ, 1?q?∞, denotes the Lq space on [−1,1] with respect to the measure , μ>0. Optimal asymptotic orders of and as m→∞ are obtained for all 1?p,τ?∞. It turns out that in many cases, the orders of are significantly smaller than the corresponding orders of the best m-term approximation by ultraspherical polynomials, which is somewhat surprising. 相似文献
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On commutators of Marcinkiewicz integrals with rough kernel 总被引:2,自引:0,他引:2
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Yuexu Zhao 《Journal of Mathematical Analysis and Applications》2008,339(1):553-565
Let X1,X2,… be a strictly stationary sequence of ρ-mixing random variables with mean zeros and positive, finite variances, set Sn=X1+?+Xn. Suppose that , , where q>2δ+2. We prove that, if for any 0<δ?1, then
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In this paper, applying the atomic decomposition and molecular characterization of the real weighted Hardy spaces , we give the weighted boundedness of the homogeneous fractional integral operator from to , and from to . 相似文献
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Dong Joo Moon Seoung Dal Jung 《Journal of Mathematical Analysis and Applications》2008,342(1):354-360
Let M be a complete Riemannian manifold and let N be a Riemannian manifold of non-positive sectional curvature. Assume that at all x∈M and at some point x0∈M, where μ0>0 is the least eigenvalue of the Laplacian acting on L2-functions on M. Let 2?q?p. Then any q-harmonic map of finite q-energy is constant. Moreover, if N is a Riemannian manifold of non-positive scalar curvature, then any q-harmonic morphism of finite q-energy is constant. 相似文献
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Kyung Soo Rim 《Journal of Mathematical Analysis and Applications》2006,324(2):1470-1477
In the p-adic vector space , we characterize those non-negative functions ψ defined on for which the weighted Hardy-Littlewood average is bounded on (1?r?∞), and on . Also, in each case, we find the corresponding operator norm ‖Uψ‖. 相似文献
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Raúl E. Curto Il Bong Jung Sang Soo Park 《Journal of Mathematical Analysis and Applications》2003,279(2):556-568
An operator T acting on a Hilbert space is said to be weakly subnormal if there exists an extension acting on such that for all . When such partially normal extensions exist, we denote by m.p.n.e.(T) the minimal one. On the other hand, for k?1, T is said to be k-hyponormal if the operator matrix is positive. We prove that a 2-hyponormal operator T always satisfies the inequality T∗[T∗,T]T?‖T‖2[T∗,T], and as a result T is automatically weakly subnormal. Thus, a hyponormal operator T is 2-hyponormal if and only if there exists B such that BA∗=A∗T and is hyponormal, where A:=[T∗,T]1/2. More generally, we prove that T is (k+1)-hyponormal if and and only if T is weakly subnormal and m.p.n.e.(T) is k-hyponormal. As an application, we obtain a matricial representation of the minimal normal extension of a subnormal operator as a block staircase matrix. 相似文献
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Andrew Bakan 《Journal of Mathematical Analysis and Applications》2008,339(1):197-216
For the sets , 1?p<∞, of positive finite Borel measures μ on the real axis with the set of algebraic polynomials P dense in Lp(R,dμ), we establish a majorization principle of their “boundaries,” i.e. for every there exists such that dμ/dν?1. A corresponding principle holds for the sets , p>0, of non-negative upper semi-continuous on R functions (weights) w such that P is dense in the space : For every there exists such that w?ω. 相似文献
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Let be the polynomial whose zeros are the j-invariants of supersingular elliptic curves over . Generalizing a construction of Atkin described in a recent paper by Kaneko and Zagier (Computational Perspectives on Number Theory (Chicago, IL, 1995), AMS/IP 7 (1998) 97-126), we define an inner product on for every . Suppose a system of orthogonal polynomials {Pn,ψ(x)}n=0∞ with respect to exists. We prove that if n is sufficiently large and ψ(x)Pn,ψ(x) is p-integral, then over . Further, we obtain an interpretation of these orthogonal polynomials as a p-adic limit of polynomials associated to p-adic modular forms. 相似文献
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Taekyun Kim 《Journal of Mathematical Analysis and Applications》2007,329(2):1472-1481
In this paper, we give an explicit p-adic expansion of
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Let , B and Aj () be real nonsingular n×n matrices, λk () be real numbers. In this paper we present a sufficient condition for the system to be a frame for . This sufficient condition also shows the stability of the system with respect to the perturbation of matrix dilation parameters and the perturbation of translation parameters . 相似文献
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Let 1<p?2 and q be such that . It is well known that the norm of the Lp-Fourier transform of the additive group is , where . For a nilpotent Lie group G, we obtain the estimate , where m is the maximal dimension of the coadjoint orbits. Such a result was known only for some particular cases. 相似文献
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Joaquín Motos María Jesús Planells César F. Talavera 《Journal of Mathematical Analysis and Applications》2008,338(1):162-174
It is proved that the Hörmander and spaces (Ω1⊂Rn, Ω2⊂Rm open sets, 1?p<∞, ki Beurling-Björck weights, k=k1⊗k2) are isomorphic whereas the iterated spaces and are not if 1<p≠q<∞. A similar result for weighted Lp-spaces of entire analytic functions is also obtained. Finally a result on iterated Besov spaces is given: and are not isomorphic when 1<q≠2<∞. 相似文献
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Di-Rong Chen 《Journal of Mathematical Analysis and Applications》2006,314(1):335-344
Starting with an initial function ?0, the cascade algorithm generates a sequence by cascade operator Qa defined by
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M. García-Huidobro 《Journal of Mathematical Analysis and Applications》2007,333(1):247-264
Let ? and θ be two increasing homeomorphisms from R onto R with ?(0)=0, θ(0)=0. Let be a function satisfying Carathéodory's conditions, and for each i, i=1,2,…,m−2, let , be a continuous function, with , ξi∈(0,1), 0<ξ1<ξ2<?<ξm−2<1.In this paper we first prove a suitable continuation lemma of Leray-Schauder type which we use to obtain several existence results for the m-point boundary value problem: