Results 21 to 30 of about 124 (105)
Sharp Hardy Identities and Inequalities on Carnot Groups
Advanced Nonlinear Studies, 2021 In this paper we establish general weighted Hardy identities for several subelliptic settings including Hardy identities on the Heisenberg group, Carnot groups with respect to a homogeneous gauge and Carnot–Carathéodory metric, general nilpotent groups ...
Flynn Joshua, Lam Nguyen, Lu Guozhen
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A Beurling‐Helson type theorem for modulation spaces
Journal of Function Spaces, Volume 7, Issue 1, Page 33-41, 2009., 2009 We prove a Beurling‐Helson type theorem on modulation spaces. More precisely, we show that the only 𝒞1 changes of variables that leave invariant the modulation spaces ℳp,q(ℝd) are affine functions on ℝd. A special case of our result involving the Sjöstrand algebra was considered earlier by A. Boulkhemair.
Kasso A. Okoudjou, Hans Feightinger
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Variation inequalities related to Schrödinger operators on weighted Morrey spaces
Open Mathematics, 2019 This paper establishes the boundedness of the variation operators associated with Riesz transforms and commutators generated by the Riesz transforms and BMO-type functions in the Schrödinger setting on the weighted Morrey spaces related to certain ...
Zhang Jing
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Analysis and Geometry in Metric Spaces, 2023 The main purpose of this article is to establish some new characterizations of the (variable) Lipschitz spaces in terms of the boundedness of commutator of multilinear fractional Calderón-Zygmund integral operators in the context of the variable exponent
Zhang Pu, Wu Jianglong
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On the degree of compactness of embeddings between weighted modulation spaces
Journal of Function Spaces, Volume 6, Issue 3, Page 303-317, 2008., 2008 The paper investigates the asymptotic behaviour of entropy and approximation numbers of compact embeddings between weighted modulation spaces.
Aicke Hinrichs +3 more
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Journal of Function Spaces, Volume 6, Issue 2, Page 107-154, 2008., 2008 A construction of Triebel‐Lizorkin type spaces associated with flexible decompositions of the frequency space ℝd is considered. The class of admissible frequency decompositions is generated by a one parameter group of (anisotropic) dilations on ℝd and a suitable decomposition function.
Lasse Borup +2 more
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Journal of Function Spaces, Volume 5, Issue 1, Page 1-8, 2007., 2007 The aim of this paper is the study of the dual of modulation spaces Mp,q(Rd) for 0 < p, q < ∞.
Masaharu Kobayashi, Hans Triebel
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Modulation spaces Mp,q for 0 < p, q?8
Journal of Function Spaces, Volume 4, Issue 3, Page 329-341, 2006., 2006 The purpose of this paper is to construct modulation spaces Mp,q(Rd) for general 0 < p, q?8, which coincide with the usual modulation spaces when 1?p,q?8, and study their basic properties including their completeness. Given any g?S(Rd) such that supp g ???{?||?|?1} and ?k?Zd g (?-ak)=1, our modulation space consists of all tempered distributions f such
Masaharu Kobayashi, Hans Triebel
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Generalized weighted Besov spaces on the Bessel hypergroup
Journal of Function Spaces, Volume 4, Issue 1, Page 91-111, 2006., 2006 In this paper we study generalized weighted Besov type spaces on the Bessel‐Kingman hypergroup. We give different characterizations of these spaces in terms of generalized convolution with a kind of smooth functions and by means of generalized translation operators. Also a discrete norm is given to obtain more general properties on these spaces.
Miloud Assal +2 more
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The random Wigner distribution of Gaussian stochastic processes with covariance in S0(ℝ2d)
Journal of Function Spaces, Volume 3, Issue 2, Page 163-181, 2005., 2005 The paper treats time‐frequency analysis of scalar‐valued zero mean Gaussian stochastic processes on ℝd. We prove that if the covariance function belongs to the Feichtinger algebra S0(ℝ2d) then: (i) the Wigner distribution and the ambiguity function of the process exist as finite variance stochastic Riemann integrals, each of which defines a stochastic
Patrik Wahlberg, Hans Feichtinger
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