Blar i forfatter "Persson, Lars Erik"

Viser treff 21-40 av 46

    • On the boundedness of subsequences of Vilenkin-Fejér means on the martingale Hardy spaces 

      Persson, Lars Erik; Tephnadze, George; Tutberidze, Giorgi (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03)
      In this paper we characterize subsequences of Fejér means with respect to Vilenkin systems, which are bounded from the Hardy space <i>H<sub>p</sub></i> to the Lebesgue space <i>L<sub>p</sub></i>, for all 0 < p < 1/2. The result is in a sense sharp.

    • Potential type operators in PDEs and their applications 

      Burtseva, Evgeniya; Lundberg, Staffan; Persson, Lars Erik; Samko, Natasha (Journal article; Peer reviewed; Tidsskriftartikkel, 2017-01)
      We prove the boundedness of Potential operator in weighted generalized Morrey space in terms of Matuszewska-Orlicz indices of weights and apply this result to the Hemholtz equation in ℝ<sup>3</sup> with a free term in such a space. We also give a short overview of some typical situations when Potential type operators arise when solving PDEs.

    • Rearrangements and jensen type inequalities related to convexity, superquadracity, strong convexity and 1-quasiconvexity 

      Abramovich, Shoshana; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09)
      In this paper we derive and discuss some new theorems related to all rearrangements of a given set in Rn , denoted (x) and use the results to prove some new Jensen type inequalities for convex, superquadratic, strongly convex and 1 -quasiconvex functions.

    • Refinements of some limit hardy-Type Inequalities via Superquadracity 

      Oguntuase, James A; Persson, Lars Erik; Fabelurin, Olanrewaju O; Adeagbo-Sheikh, Abdulaziz G (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-03)
      Refinements of some limit Hardy-type inequalities are derived and discussed using the concept of superquadracity. We also proved that all three constants appearing in the refined inequalities obtained are sharp. The natural turning point of our refined Hardy inequality is p=2 and for this case we have even equality.

    • A sharp boundedness result for restricted maximal operators of Vilenkin-Fourier series on martingale Hardy spaces 

      Blahota, Istvan; Nagy, Karoly; Persson, Lars Erik; Tephnadze, George (Journal article; Peer reviewed, 2018-09-20)
      The restricted maximal operators of partial sums with respect to bounded Vilenkin systems are investigated. We derive the maximal subspace of positive numbers, for which this operator is bounded from the Hardy space H p to the Lebesgue space L p for all 0<p≤1 . We also prove that the result is sharp in a particular sense.

    • Sharp Hp-Lp type inequalities of weighted maximal operators of Vilenkin-Nörlund means and its applications 

      Baramidze, Lasha; Persson, Lars Erik; Tephnadze, G; Wall, P (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-01)
      We prove and discuss some new Hp-Lp type inequalities of weighted maximal operators of Vilenkin-Nörlund means with monotone coefficients. It is also proved that these inequalities are the best possible in a special sense. We also apply these results to prove strong summability for such Vilenkin-Nörlund means. As applications, both some well-known and new results are pointed out.

    • Some Fourier inequalities for orthogonal systems in Lorentz–Zygmund spaces 

      Akishev, Gabdolla; Persson, Lars Erik; Seger, Andreas (Journal article; Peer reviewed, 2019-06-13)
      A number of classical inequalities and convergence results related to Fourier coefficients with respect to unbounded orthogonal systems are generalized and complemented. All results are given in the case of Lorentz–Zygmund spaces.

    • Some Higher Order Hardy Inequalities 

      Kufner, Alois; Kuliev, Komil; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-03-26)
      We investigate the k-th order Hardy inequality (1.1) for functions satisfying rather general boundary conditions (1.2), show which of these conditions are admissible and derive sufficient, and necessary and sufficient, conditions (for 0 < q < ∞, p > 1) on u, v for (1.1) to hold.

    • Some inequalities for Cesàro means of double Vilenkin-Fourier series 

      Tephnadze, G; Persson, Lars Erik (Journal article; Peer reviewed; Tidsskriftartikkel, 2018-12-19)
      In this paper, we state and prove some new inequalities related to the rate of Lp approximation by Cesàro means of the quadratic partial sums of double Vilenkin–Fourier series of functions from Lp.

    • Some inequalities related to strong convergence of Riesz logarithmic means 

      Lukkassen, Dag; Persson, Lars Erik; Tephnadze, George; Tutberidze, Giorgi (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-23)
      In this paper we derive a new strong convergence theorem of Riesz logarithmic means of the one-dimensional Vilenkin–Fourier (Walsh–Fourier) series. The corresponding inequality is pointed out and it is also proved that the inequality is in a sense sharp, at least for the case with Walsh–Fourier series.

    • Some new (Hp,Lp) type inequalitiesof maximal operators of Vilenkin-Nörlund means with non-decreasing coefficients 

      Persson, Lars Erik; Tephanadze, G; Wall, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12)
      In this paper we prove and discuss some new (H<sub>p</sub>,L<sub>p</sub>) type inequalities of maximal operators of Vilenkin-Nörlund means with non-decreasing coefficients. We also apply these inequalities to prove strong convergence theorems of such Vilenkin-N ¨orlund means. These inequalities are the best possible in a special sense. As applications, both some well-known and new results are pointed out.

    • Some new estimates of the ‘Jensen gap’ 

      Abramovich, Shoshana; Persson, Lars Erik (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-02-01)

    • Some new Fourier inequalities for unbounded orthogonal systems in Lorentz-Zygmund spaces 

      Akishev, Gabdolla; Lukkassen, Dag; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-20)
      In this paper we prove some essential complements of the paper (J. Inequal. Appl. 2019:171, 2019) on the same theme. We prove some new Fourier inequalities in the case of the Lorentz–Zygmund function spaces L q,r (logL ) α Lq,r(log⁡L)α involved and in the case with an unbounded orthonormal system. More exactly, in this paper we prove and discuss some new Fourier inequalities of this type for ...

    • Some new Hardy-type inequalities for Riemann-Liouville fractional q-integral operator 

      Persson, Lars Erik; Shaimardan, Serikbol (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-09-24)
      We consider the q-analog of the Riemann-Liouville fractional q-integral operator of order n∈Nn∈N. Some new Hardy-type inequalities for this operator are proved and discussed.

    • Some new Hardy-type inequalities in q-analysis 

      Baiarystanov, A.O.; Persson, Lars Erik; Shaimardan, S.; Temirkhanova, A. (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-09)
      We derive necessary and sufficient conditions (of Muckenhoupt-Bradley type) for the validity of q -analogs of (r, p) -weighted Hardy-type inequalities for all possible positive values of the parameters r and p . We also point out some possibilities to further develop the theory of Hardy-type inequalities in this new direction.

    • Some New Iterated Hardy-Type Inequalities 

      Gogatishvili, A; Mustafayev, RC; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-12-10)

    • Some new iterated Hardy-type inequalities: the case theta=1 

      Gogatishvili, Amiran; Mustafayev, Rza; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-11-08)
      In this paper we characterize the validity of the Hardy-type inequality &#8741 &#8741 &#8747 <sub>s</sub>&#8734) h(z)dz &#8741 p,u,(0,t) &#8741 q,w,(=,&#8734≤ c&#8741h&#8741 1,v(0,&#8734) where 0 < p < ∞,0< q ≤ +∞, u, w and v are weight functions on (0,∞). It is pointed out that this characterization can be used to obtain new characterizations for the boundedness between weighted Lebesgue spaces ...

    • SOME NEW REFINEMENTS OF HARDY-TYPE INEQUALITIES 

      Oguntuase, J. A.; Fabelurin, Olanrewaju O; Persson, Lars Erik; Adeleke, EO (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-11)
      We obtain some further refinements of Hardy-type inequalities via superqudraticity technique. Our results both unify and further generalize several results on refinements of Hardy-type inequalities in the literature.

    • Some new Two-Sided Inequalities concerning the Fourier Transform 

      Kopezhanova, Aigerim; Nursultanov, Erlan; Persson, Lars Erik (Journal article; Peer reviewed; Tidsskriftartikkel, 2017)
      The classical Hausdorff-Young and Hardy-Littlewood-Stein inequalities do not hold for p > 2. In this paper we prove that if we restrict to net spaces we can even derive a two-sided estimate for all p > 1. In particular, this result generalizes a recent result by Liflyand E. and Tikhonov S. [7] (MR 2464253).

    • Some sharp inequalities for integral operators with homogeneous kernel 

      Lukkassen, Dag; Persson, Lars Erik; Samko, Stefan G. (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-04-09)
      One goal of this paper is to show that a big number of inequalities for functions in Lp(R+), p ≥ 1, proved from time to time in journal publications are particular cases of some known general results for integral operators with homogeneous kernels including, in particular, the statements on sharp constants. Some new results are also included, e.g. the similar general equivalence result is proved and ...