共查询到20条相似文献,搜索用时 31 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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Giuseppe Zampieri 《Journal of Mathematical Analysis and Applications》2003,283(1):150-158
Let be a CR mapping between real analytic generic submanifolds M, M1 of and , respectively. According to Webster's theory (Proc. Amer. Math. Soc. 86 (1982) 236-240) and its further developments, f has holomorphic extension to a full neighborhood of M in when the following requirements are fulfilled: f extends to a wedge W continuous up to M; f is of class Ck; (where denotes the complex tangent bundle); M1 is “k-nondegenerate.” We deal here with the case where is strictly smaller than but is still real analytic in suitable sense. We show that a suitably refined condition of k-nondegeneracy still entails holomorphic extension of f. 相似文献
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Tomoyoshi Ohwada Guoxing Ji Atsushi Hasegawa 《Journal of Mathematical Analysis and Applications》2006,315(1):216-224
Let G be a compact abelian group with the totally ordered dual group which admits the positive semigroup . Let N be a von Neumann algebra and be an automorphism group of on N. We denote to the analytic crossed product determined by N and α. We show that if is a maximal σ-weakly closed subalgebra of , then induces an archimedean order in . 相似文献
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Liangping Jiang 《Journal of Mathematical Analysis and Applications》2005,301(2):378-383
The classical criterion of asymptotic stability of the zero solution of equations x′=f(t,x) is that there exists a positive definite function V which has infinitesimal upper bound such that is negative definite. In this paper we prove that if is bounded then the condition that is negative definite can be weakened and replaced by that and is negative definite. 相似文献
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Xin-Han Dong 《Journal of Mathematical Analysis and Applications》2004,296(2):650-657
Let denote the class of functions f which are areally mean p-valent and have k maximal growth directions in Δ={z:|z|<1}. In this paper we give an asymptotic formula of the mean square of the logarithmic derivative f′/f for with some restricted condition. This generalizes the corresponding result in [J. Anal. Math. 36 (1979) 36-43]. Also we construct a function which does not satisfy this asymptotic formula. 相似文献
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Jian-Ping Fang 《Journal of Mathematical Analysis and Applications》2007,332(2):1393-1407
In this paper, we construct a new q-exponential operator and obtain some operator identities. Using these operator identities, we give a formal extension of Jackson's transformation formula. A formal extension of Bailey's summation and an extension of the Sears terminating balanced transformation formula are also derived by our operator method. In addition, we also derive several interesting a formal extensions involving multiple sum about three terms of Sears transformation formula and Heine's transformation formula. 相似文献
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Emin Özça? ?nci Ege Ha?met Gürçay 《Journal of Mathematical Analysis and Applications》2007,326(1):101-107
The distributions and were defined as the neutrix limit of the sequences and respectively for , see [J.D. Nicholos, B. Fisher, The distribution composition , J. Math. Anal. Appl. 258 (2001) 131-145; B. Fisher, On defining the distribution , Univ. u Novom Sadu Zb. Rad. Prirod. Mat. Fak. Ser. Mat. 15 (1985) 119-129]. We here consider these distributions when r=0. In other words, we define the sth powers of the Heaviside function H(x) in the distributional sense for negative integers. Further compositions are also considered. 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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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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In this paper, we show that if is an n-dimensional subspace of L(V) such that every nonzero transformation of has rank greater than or equal to 2n−1 then is algebraically reflexive. If is an n-dimensional subspace of B(H) such that every nonzero transformation of has rank greater than or equal to 2n−1 then is hyperreflexive. We also consider how to construct some new hyperreflexive subspaces. 相似文献
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Tian-Xiao Pang Zheng-Yan Lin 《Journal of Mathematical Analysis and Applications》2007,334(2):1246-1259
Let be a sequence of independent and identically distributed positive random variables, which is in the domain of attraction of the normal law, and tn be a positive, integer random variable. Denote , , where denotes the sample mean. Then we show that the self-normalized random product of the partial sums, , is still asymptotically lognormal under a suitable condition about tn. 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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R. Balasubramanian D.J. Prabhakaran 《Journal of Mathematical Analysis and Applications》2004,293(1):355-373
For β<1, let denote the class of all normalized analytic functions f such that