Results 11 to 20 of about 91 (79)
Concentration-compactness principle associated with Adams' inequality in Lorentz-Sobolev space
Advanced Nonlinear Studies, 2022 The concentration-compactness principle of Lions type in Euclidean space relies on the Pólya-Szegö inequality, which is not available in non-Euclidean settings.
Li Dongliang, Zhu Maochun
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On the approximation by trigonometric polynomials in weighted Lorentz spaces
Journal of Function Spaces, Volume 8, Issue 1, Page 67-86, 2010., 2010 We obtain estimates of structural characteristics of 2π‐periodic functions by the best trigonometric approximations in weighted Lorentz spaces, and show that the order of generalized modulus of smoothness depends not only on the rate of the best approximation, but also on the metric of the spaces.
Vakhtang Kokilashvili +2 more
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Weighted CBMO estimates for commutators of matrix Hausdorff operator on the Heisenberg group
Open Mathematics, 2020 In this article, we study the commutators of Hausdorff operators and establish their boundedness on the weighted Herz spaces in the setting of the Heisenberg group.
Ajaib Amna, Hussain Amjad
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A Korovkin theorem in multivariate modular function spaces
Journal of Function Spaces, Volume 7, Issue 2, Page 105-120, 2009., 2009 In this paper a modular version of the classical Korovkin theorem in multivariate modular function spaces is obtained and applications to some multivariate discrete and integral operators, acting in Orlicz spaces, are given.
Carlo Bardaro +2 more
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A criterion of weak compactness for operators on subspaces of Orlicz spaces
Journal of Function Spaces, Volume 6, Issue 3, Page 277-292, 2008., 2008 We give a criterion of weak compactness for the operators on the Morse‐Transue space MΨ, the subspace of the Orlicz space LΨ generated by L∞.
Pascal Lefèvre +4 more
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On the trace space of a Sobolev space with a radial weight
Journal of Function Spaces, Volume 6, Issue 3, Page 259-276, 2008., 2008 Our concern in this paper lies with trace spaces for weighted Sobolev spaces, when the weight is a power of the distance to a point at the boundary. For a large range of powers we give a full description of the trace space.
Helmut Abels +3 more
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Extremal points without compactness in L1(μ)
Journal of Function Spaces, Volume 5, Issue 2, Page 199-211, 2007., 2007 We investigate the existence of extremal points and the Krein‐MIlman representation A=co̅ExtA of bounded convex subsets of L1(μ) which are only closed with respect to the topology of μ‐a.e. convergence.
Anna Martellotti, Jürgen Appell
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A note on maximal operator on ℓ{pn} and Lp(x)(ℝ)
Journal of Function Spaces, Volume 5, Issue 1, Page 49-88, 2007., 2007 We consider a discrete analogue of Hardy‐Littlewood maximal operator on the generalized Lebesque space ℓ{pn} of sequences defined on ℤ. It is known a necessary and sufficient condition P which guarantees an existence of a real number p > 1 such that the norms in the space ℓ{pn} and in the classical space ℓp are equivalent.
Aleš Nekvinda, Pankaj Jain
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Weighted norm inequalities and indices
Journal of Function Spaces, Volume 4, Issue 1, Page 43-71, 2006., 2006 We extend and simplify several classical results on weighted norm inequalities for classical operators acting on rearrangement invariant spaces using the theory of indices. As an application we obtain necessary and sufficient conditions for generalized Hardy type operators to be bounded on ?p(w), ?p,8(w), Gp(w) and Gp,8(w).
Joaquim Martín +2 more
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New classes of rearrangement‐invariant spaces appearing in extreme cases of weak interpolation
Journal of Function Spaces, Volume 4, Issue 3, Page 275-304, 2006., 2006 We study weak type interpolation for ultrasymmetric spaces L?,E i.e., having the norm ??(t)f*(t)?E˜, where ?(t) is any quasiconcave function and E˜ is arbitrary rearrangement‐invariant space with respect to the measure d t /t. When spaces L?,E are not “too close” to the endpoint spaces of interpolation (in the sense of Boyd), the optimal interpolation ...
Evgeniy Pustylnik +2 more
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