Pseudodifferential Operators Approach to Singular Integral Operators in Weighted Variable Exponent Lebesgue Spaces on Carleson Curves

The main results of the paper are: (1) The boundedness of singular integral operators in the variable exponent Lebesgue spaces L ^p(·)(Γ, w) on a class of composed Carleson curves Γ where the weights w have a finite set of oscillating singularities. The proof of this result is based on the boundedness of Mellin pseudodifferential operators on the spaces L^p(·)(\mathbbR ₊,dm){L^{p(\cdot )}(\mathbb{R} _{+},d\mu)} where dμ is an invariant measure on multiplicative group ${\mathbb{R}_{+}=\left\{r\in \mathbb{R}:r >0 \right\}}${\mathbb{R}_{+}=\left\{r\in \mathbb{R}:r >0 \right\}}. (2) Criterion of local invertibility of singular integral operators with piecewise slowly oscillating coefficients acting on L ^p(·)(Γ, w) spaces. We obtain this criterion from the corresponding criteria of local invertibility at the point 0 of Mellin pseudodifferential operators on \mathbbR₊{\mathbb{R}_{+}} and local invertibility of singular integral operators on \mathbbR{\mathbb{R}}. (3) Criterion of Fredholmness of singular integral operators in the variable exponent Lebesgue spaces L ^p(·)(Γ, w) where Γ belongs to a class of composed Carleson curves slowly oscillating at the nodes, and the weight w has a finite set of slowly oscillating singularities.     

关于变指数加权Sobolev空间的拟连续性

本文给出了一些关于变指数加权Sobolev空间拟连续性的精确刻画. 进而在拟连续的意义下得到变指数加权Sobolev空间唯一性结果.     

On Some Properties of Convolutions in Variable Exponent Lebesgue Spaces

A convolution in the variable exponent Lebesgue spaces \(L_{2\pi }^{p\left( \cdot \right) }\) is defined and its basic properties are investigated. It is also proved that this convolution can be approximated in \(L_{2\pi }^{p\left( \cdot \right) }\) by the finite linear combinations of Steklov means of the original function.     

Weighted Grand Lebesgue Space with a Mixed Norm and Integral Operators

Doklady Mathematics - Weighted grand Lebesgue spaces with mixed norms are introduced, and criteria for the boundedness of strong maximal functions and Riesz transforms in these spaces are given.     

Anisotropic Elliptic Nonlinear Obstacle Problem with Weighted Variable Exponent

In this paper, we are concerned with a show the existence of a entropy solution to the obstacle problem associated with the equation of the type :$\begin{cases}Au+g(x,u,∇u) = f & {\rm in} & Ω \\ u=0 & {\rm on} & ∂Ω \end{cases}$where $\Omega$ is a bounded open subset of $\;\mathbb{R}^{N}$, $N\geq 2$, $A\,$ is an operator of Leray-Lions type acting from $\; W_{0}^{1,\overrightarrow{p}(.)} (\Omega,\ \overrightarrow{w}(.))\;$ into its dual $\; W_{0}^{-1,\overrightarrow{p}'(.)} (\Omega,\ \overrightarrow{w}^*(.))$ and $\,L^1\,-\,$deta. The nonlinear term $\;g\,$: $\Omega\times \mathbb{R}\times \mathbb{R}^{N}\longrightarrow \mathbb{R} $ satisfying only some growth condition.     

Parameterized Littlewood-Paley Operators and Their Commutators on Lebesgue Spaces with Variable Exponent

In this paper, by applying the technique of the sharp maximal function and the equivalent representation of the norm in the Lebesgue spaces with variable exponent, the boundedness of the parameterized Littlewood-Paley operators, including the parameterized Lusin area integrals and the parameterized Littlewood-Paley g*λ-functions, is established on the Lebesgue spaces with variable exponent. Furthermore,the boundedness of their commutators generated respectively by BMO functions and Lipschitz functions are also obtained.     

Some Modular Inequalities in Lebesgue Spaces with Variable Exponent on the Complex Plane

Mathematical Notes - We consider the modular inequalities for some linear operators on Lebesgue spaces with variable exponent on the complex plane. The main results show that the variable exponent...     

Jacobi Polynomials,Weighted Sobolev Spaces and Approximation Results of Some Singularities

In this paper, we give some polynomial approximation results in a class of weighted Sobolev spaces, which are related to the Jacobi operator. We further give some embeddings of those weighted Sobolev spaces into usual ones and into spaces of continuous functions, in order to use the above approximation results in the p‐version (or the spectral method) of some finite or boundary element methods. Finally, two typical examples of the polynomial approximation of some singularities of boundary value problems in polygonal or polyhedral domains are presented.     

Clifford Valued Weighted Variable Exponent Spaces with an Application to Obstacle Problems

In this paper, we introduce the weighted variable exponent spaces in the context of Clifford algebras. After discussing the properties of these spaces, we obtain the existence of weak solutions for obstacle problems for nondegenerate A-Dirac equations with variable growth in the setting of these spaces. Furthermore, we also obtain the existence and uniqueness of weak solutions to the scalar parts of nondegenerate A-Dirac equations in Dirac Sobolev spaces.     

变指数Herz-Hardy空间上的变指标分数次积分算子及其交换子

基于变指数函数空间和分数次积分算子的一些基本性质,应用变指数Herz-Hardy空间上的原子分解定理,利用Holder不等式和Jensen不等式,证明了具有齐性核的变指标分数次积分算子及其交换子在变指数Herz-Hardy空间上的有界性.     

含参数加权极大Lebesgue空间中次线性算子的有界性质

引进一类含参数加权极大Lebesgue空间并得到满足一定尺寸条件的次线性算子在该类空间中的有界性质.特别地,还考虑了该类空间上次线性算子与BMO函数生成交换子的相应有界性质.     

Weighted Estimates of Variable Kernel Fractional Integral and Its Commutators on Vanishing Generalized Morrey Spaces with Variable Exponent

In this paper, the authors obtain the boundedness of the fractional integral operators with variable kernels on the variable exponent generalized weighted Morrey spaces and the variable exponent vanishing generalized weighted Morrey spaces. And the corresponding commutators generated by BMO function are also considered.     

欧氏空间中等角基的性质

等角基是正交基的推广,等角基具有和正交基相似的性质,因此研究等角基的性质能够为研究欧氏空间提供一种工具,加深对欧氏空间的了解.本文主要把n维欧氏空间中正交基的一些性质推广到等角基上,得到了五个关于等角基性质的定理.     

θ-型C-Z算子在加权变指数Morrey空间上的有界性

在满足一定的正则性假设条件下,建立了θ-型Calderón-Zygmund算子T_θ在一类变指数Lebesgue空间上的加权有界性.进一步得到了T_θ在加权变指数Herz空间和Herz-Morrey空间上的有界性.另外,还证明了相应的交换子[b,T_θ]在广义加权变指数Morrey空间上是有界的.     

Approximation by Polynomials in Sobolev Spaces with Jacobi Weight

Polynomial approximation is studied in the Sobolev space \(W_p^r(w_{\alpha ,\beta })\) that consists of functions whose r-th derivatives are in weighted \(L^p\) space with the Jacobi weight function \(w_{\alpha ,\beta }\). This requires simultaneous approximation of a function and its consecutive derivatives up to s-th order with \(s \le r\). We provide sharp error estimates given in terms of \(E_n(f^{(r)})_{L^p(w_{\alpha ,\beta })}\), the error of best approximation to \(f^{(r)}\) by polynomials in \(L^p(w_{\alpha ,\beta })\), and an explicit construction of the polynomials that approximate simultaneously with the sharp error estimates.     

Maximal Operator in Variable Exponent Generalized Morrey Spaces on Quasi-metric Measure Space

We consider generalized Morrey spaces \({\mathcal{L}^{p(\cdot),\varphi(\cdot)}( X )}\) on quasi-metric measure spaces \({X,d,\mu}\), in general unbounded, with variable exponent p(x) and a general function \({\varphi(x,r)}\) defining the Morrey-type norm. No linear structure of the underlying space X is assumed. The admission of unbounded X generates problems known in variable exponent analysis. We prove the boundedness results for maximal operator known earlier only for the case of bounded sets X. The conditions for the boundedness are given in terms of the so called supremal inequalities imposed on the function \({\varphi(x,r)}\), which are weaker than Zygmund-type integral inequalities often used for characterization of admissible functions \({\varphi}\). Our conditions do not suppose any assumption on monotonicity of \({\varphi(x,r)}\) in r.     

欧氏空间中等角基的性质

等角基是正交基的推广,等角基具有和正交基相似的性质,因此研究等角基的性质能够为研究欧氏空间提供一种工具,加深对欧氏空间的了解．本文主要把n维欧氏空间中正交基的一些性质推广到等角基上,得到了五个关于等角基性质的定理．