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Given an approximately continuous function $f$ in an Orlicz space $L^\Phi([a,b]),$ for a suitable class of convex functions $\Phi,$ we employ a characterization of the best monotone approximation set to establish its continuity, which in…

Functional Analysis · Mathematics 2026-04-29 Ana Benavente , Juan Costa Ponce , Sergio Favier

In mathematical modelling, the data and solutions are represented as measurable functions and their quality is oftentimes captured by the membership to a certain function space. One of the core questions for an analysis of a model is the…

Functional Analysis · Mathematics 2022-11-22 Vít Musil , Luboš Pick , Jakub Takáč

In the Orlicz type spaces ${\mathcal S}_{M}$, we prove direct and inverse approximation theorems in terms of the best approximations of functions and moduli of smoothness of fractional order. We also show the equivalence between moduli of…

Classical Analysis and ODEs · Mathematics 2020-04-22 Stanislav Chaichenko , Andrii Shidlich , Fahreddin Abdullayev

We give a characterization of those functions whose all translates are complete in certain Orlicz space $L^{\Phi}(\mathbb{R})$. As a consequence, we identified those discrete sets $\Lambda \subseteq \mathbb{R}$ such that there exists a…

Functional Analysis · Mathematics 2023-11-29 Bhawna Dharra , S. Sivananthan

In this paper we obtained some direct and inverse theorems of approximation theory for $\psi$-differentiable functions in the metric weighted Orlicz spaces with weights, which belong to the class of Muckenhoupt.

Classical Analysis and ODEs · Mathematics 2015-01-13 Stanislav Chaichenko

In terms of the best approximations of functions and generalized moduli of smoothness, direct and inverse approximation theorems are proved for Besicovitch almost periodic functions whose Fourier exponent sequences have a single limit point…

Classical Analysis and ODEs · Mathematics 2025-09-30 Stanislav Chaichenko , Andrii Shidlich , Tetiana Shulyk

Approximative properties of linear summation methods of Fourier series are considered in the Orlicz type spaces ${\mathcal S}_{M}$. In particular, in terms of approximations by such methods, constructive characteristics are obtained for…

Classical Analysis and ODEs · Mathematics 2019-10-29 Stanislav Chaichenko , Viktor Savchuk , Andrii Shidlich

In the dual $L_{\Phi^*}$ of a $\Delta_2$-Orlicz space $L_\Phi$, that we call a dual Orlicz space, we show that a proper (resp. finite) convex function is lower semicontinuous (resp. continuous) for the Mackey topology…

Functional Analysis · Mathematics 2018-01-03 Freddy Delbaen , Keita Owari

We investigate Sobolev spaces $W^{1,\Phi}$ associated to Musielak-Orlicz spaces $L^\Phi$. We first present conditions for the boundedness of the Voltera operator in $L^\Phi$. Employing this, we provide necessary and sufficient conditions…

Functional Analysis · Mathematics 2021-12-14 Anna Kamińska , Mariusz Żyluk

In this paper, we consider the best multivalued polynomial approximation operator for functions in an Orlicz Space $L^{\varphi}(\Omega)$. We obtain its characterization involving $\psi^-$ and $\psi^+$, which are the left and right…

Classical Analysis and ODEs · Mathematics 2025-05-28 Sonia Acinas , Sergio Favier , Rosa Lorenzo

We obtain the exact values of some important approximative quantities (such as, the best approximation, the basis width, Kolmogorov's width and the best $n$-term approximation) of certain sets of images of the diagonal operators in the…

Numerical Analysis · Mathematics 2016-10-03 Andriy L. Shidlich , Stanislav O. Chaichenko

We study point-wise estimates for the modified Riesz potential. We show that the point-wise estimates imply embeddings into Orlicz spaces from the L^1_p-space where the functions are defined in non-smooth domains. The Orlicz functions…

Functional Analysis · Mathematics 2015-08-04 Petteri Harjulehto , Ritva Hurri-Syrjänen

The optimal Orlicz target space is exhibited for embeddings of fractional-order Orlicz-Sobolev spaces in $\mathbb R^n$. An improved embedding with an Orlicz-Lorentz target space, which is optimal in the broader class of all…

Functional Analysis · Mathematics 2020-01-17 Angela Alberico , Andrea Cianchi , Luboš Pick , Lenka Slavíková

We consider approximation by functions with finite support and characterize its approximation spaces in terms of interpolation spaces and Lorentz spaces.

Classical Analysis and ODEs · Mathematics 2017-07-05 Bo Ling , Yongping Liu

In Musilak-Orlicz type spaces ${\mathcal S}_{\bf M}$, direct and inverse approximation theorems are obtained in terms of the best approximations of functions and generalized moduli of smoothness. The question of the exact constants in…

Classical Analysis and ODEs · Mathematics 2021-05-07 Fahreddin Abdullayev , Stanislav Chaichenko , Andrii Shidlich

A new class of convex functions called functions, Young functions, strong Young functions and Orlicz functions are introduced by relaxing the definitions of functions, Young functions, strong Young functions and Orlicz functions. Then, new…

Functional Analysis · Mathematics 2019-05-16 Abdulhameed Qahtan Abbood Altai , Nada Mohammed Abbas Alsafar

Several local geometric properties of Orlicz space $L_\phi$ are presented for an increasing Orlicz function $\phi$ which is not necessarily convex, and thus $L_\phi$ does not need to be a Banach space. In addition to monotonicity of $\phi$…

Functional Analysis · Mathematics 2019-11-26 Anna Kamińska , Mariusz Żyluk

Democracy functions of wavelet admissible bases are computed for weighted Orlicz Spaces in terms of its fundamental function. In particular, we prove that these bases are greedy if and only if the Orlicz space is a Lebesgue space. Also,…

History and Overview · Mathematics 2009-11-26 Maria de Natividade

We study the finite element approximation of problems involving the weighted $\Phi$-Laplacian, where $\Phi$ is an $N$-function and the weight belongs to the class $A_\Phi$. In particular, we consider a boundary value problem and an obstacle…

Numerical Analysis · Mathematics 2025-08-15 Enrique Otarola , Abner J. Salgado

The concept of mixed norm spaces has emerged as a significant interest in fields such as harmonic analysis. In addition, the problem of function approximation through sampling series has been particularly noteworthy in the realm of…

Functional Analysis · Mathematics 2025-07-24 Priyanka Majethiya , Shivam Bajpeyi , Dhiraj Patel
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