Results 1 to 10 of about 467 (33)
Journal of Function Spaces, Volume 8, Issue 3, Page 215-244, 2010., 2010 We consider non‐standard Hölder spaces Hλ(⋅)(X) of functions f on a metric measure space (X, d, μ), whose Hölder exponent λ(x) is variable, depending on x ∈ X. We establish theorems on mapping properties of potential operators of variable order α(x), from such a variable exponent Hölder space with the exponent λ(x) to another one with a “better ...
Natasha Samko +3 more
wiley +1 more source
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
wiley +1 more source
A convolution type characterization for Lp ‐ multipliers for the Heisenberg group
Journal of Function Spaces, Volume 5, Issue 2, Page 175-182, 2007., 2007 It is well known that if m is an Lp ‐ multiplier for the Fourier transform on ℝn(1 < p < ∞) , then there exists a pseudomeasure σ such that Tmf = σ*f. A similar result is proved for the group Fourier transform on the Heisenberg group Hn. Though this result is already known in generality for amenable groups, a simple proof is provided in this paper.
R. Radha +2 more
wiley +1 more source
Rough singular integrals on product spaces
International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 67, Page 3671-3684, 2004., 2004 We study the mapping properties of singular integral operators defined by mappings of finite type. We prove that such singular integral operators are bounded on the Lebesgue spaces under the condition that the singular kernels are allowed to be in certain block spaces.
Ahmad Al-Salman, Hussain Al-Qassem
wiley +1 more source
Marcinkiewicz integrals along subvarieties on product domains
International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 72, Page 4001-4011, 2004., 2004 We study the Lp mapping properties of a class of Marcinkiewicz integral operators on product domains with rough kernels supported by subvarieties.
Ahmad Al-Salman
wiley +1 more source
Rate preservation of double sequences under l‐l type transformation
International Journal of Mathematics and Mathematical Sciences, Volume 30, Issue 10, Page 637-643, 2002., 2002 Following the concepts of divergent rate preservation for ordinary sequences, we present a notion of rates preservation of divergent double sequences under l‐l type transformations. Definitions for Pringsheim limit inferior and superior are also presented.
Richard F. Patterson
wiley +1 more source
Rough Marcinkiewicz integral operators
International Journal of Mathematics and Mathematical Sciences, Volume 27, Issue 8, Page 495-503, 2001., 2001 We study the Marcinkiewicz integral operator M𝒫f(x)=(∫−∞∞|∫|y|≤2tf(x−𝒫(y))(Ω(y)/|y|n−1)dy|2dt/22t)12/, where 𝒫 is a polynomial mapping from ℝn into ℝd and Ω is a homogeneous function of degree zero on ℝn with mean value zero over the unit sphere Sn−1. We prove an Lp boundedness result of M𝒫 for rough Ω.
Hussain Al-Qassem, Ahmad Al-Salman
wiley +1 more source
Local properties of Fourier series
International Journal of Mathematics and Mathematical Sciences, Volume 23, Issue 10, Page 703-709, 2000., 2000 A theorem on local property of |N¯,pn|k summability of factored Fourier series, which generalizes some known results, and also a general theorem concerning the |N¯,pn|k summability factors of Fourier series have been proved.
Hüseyin Bor
wiley +1 more source
Boundedness of the twisted paraproduct [PDF]
Rev. Mat. Iberoam. 28 (2012), no. 4, 1143-1164, 2010 We prove L^p estimates for a two-dimensional bilinear operator of paraproduct type. This result answers a question posed by Demeter and Thiele in [3].
arxiv +1 more source
Operator-Valued $L_{q}\to L_{p}$ Fourier Multipliers [PDF]
arXiv, 2008 This paper is withdrawn due to some gaps in the ...
arxiv