广义Calderón-Zygmund算子交换子在Hardy型空间上的有界性

[b,T]表示由Lipschitz函数b与广义Calderon-Zygmund算子T生成的交换子．本文研究了[b,T]在经典Hardy空间和Herz型Hardy空间上的有界性,并且在临界点情形证明了该交换子是从Hardy空间到弱Lebesgue空间以及Herz型Hardy到弱Herz空间有界的．     

各向异性弱Hardy空间与插值定理

引入伴随于非常一般离散伸缩群的各向异性弱Hardy空间, 并给出了该空间的原子分解. 作为应用, 证明了与这些弱Hardy空间相关的几个插值定理, 得到了某些奇异积分算子在各向异性弱Hardy空间的有界性.     

多线性交换子在Hardy型空间上的有界性

利用原子分解得到了具有Caldern-Zygmund核的奇异积分多线性交换子在变形Hardy空间、变形弱Hardy空间及变形Herz型Hardy空间上的有界性.     

广义Calder\''{o}n-Zygmund算子交换子在Hardy型空间上的有界性 (英)

$[b,T]$表示由Lipschitz函数$b$与广义Calder\'{o}n-Zygmund算子$T$生成的交换子.本文研究了$[b,T]$在经典Hardy空间和Herz型Hardy空间上的有界性,并且在临界点情形证明了该交换子是从Hardy空间到弱Lebesgue空间以及Herz型Hardy到弱Herz空间有界的.     

Calderon-Zygmund型算子在加权Herz型Hardy空间上的弱型估计

本文引入了加权弱Herz型Hardy空间，并证明了当a=n(1-1/q) δ时，胡国恩和陆善镇等在文[1]中所考虑的两类Calderon-Zygmund型算子分别连续地映加权Herz型Hardy空间到加权弱Herz空间和加权弱Herz型Hardy空间。     

一类分数次积分算子在Herz型Hardy空间上的有界性

通过放宽尺寸条件,得到了一类具有分数次积分性质的次线性算子从Herz型Hardy空间到(弱)Herz型Hardy空间有界性的判定条件,以及端点处的弱型估计.     

分数次积分交换子在加权Herz型Hardy空间上的有界性质

本文研究了由分数次积分I_l与加权Lipschitz函数b生成的交换子[b,I_l]在加权Herz型Hardy空间上的估计.利用加权Herz型Hardy空间的分解理论,得到了交换子[b,I_l]从加权Herz型Hardy空间到(弱)加权Herz空间上的有界性质.     

弱Hardy鞅空间与鞅的弱原子分解

定义了一些弱Hardy鞅空间和3种类型的弱原子. 它们与经典的H_p鞅论中的Hardy鞅空间和原子形成对应. 然后证明了弱Hardy鞅空间上的3个弱原子分解定理. 利用鞅的弱原子分解, 给出了弱Hardy鞅空间上的次线性算子有界的一个充分条件. 利用这个条件, 得到关于鞅的一系列弱H_p范数不等式和弱(p,p)型不等式, 以及各个弱Hardy鞅空间的连续嵌入关系. 这些不等式是经典的H_p鞅论中基本不等式的弱型对应.     

B值弱Hardy两指标鞅空间的原子分解

本文研究了B值弱Hardy两指标鞅空间的原子分解理论,利用原子分解的方法, 获得了B值弱Hardy两指标鞅空间的相互嵌入关系,所得结果联系于Banach空间的几何性质.     

交换子在Hardy型空间上的有界性

[b,T]表示由函数b∈Lip_b (Rⁿ)与Calderón-Zygmund奇异积分算子T生成的交换子. 研究了[b,T]在经典Hardy空间和Herz型Hardy空间上的有界性质, 对端点空间上的有界性给出了等价特征刻画, 并在端点情形证明了该交换子是从Hardy型空间到弱Lebesgue空间或弱Herz空间有界的.     

On the embedding of BV space into Besov-Orlicz space

We give a sufficient (and, in the case of a compact domain, a necessary) condition for the embedding of Sobolev space of functions with integrable gradient into Besov-Orlicz spaces to be bounded. The condition has a form of a simple integral inequality involving Young and weight functions. We provide an example with Matuszewska-Orlicz indices of involved Orlicz norm equal to one. The main tool is the molecular decomposition of functions from a BV space.     

Planar and affine spaces

In this note, we characterize finite three-dimensional affine spaces as the only linear spaces endowed with set Ω of proper subspaces having the properties (1) every line contains a constant number of points, say n, with n>2; (2) every triple of noncollinear points is contained in a unique member of Ω; (3) disjoint or coincide is an equivalence relation in Ω with the additional property that every equivalence class covers all points. We also take a look at the case n=2 (in which case we have a complete graph endowed with a set Ω of proper complete subgraphs) and classify these objects: besides the affine 3-space of order 2, two small additional examples turn up. Furthermore, we generalize our result in the case of dimension greater than three to obtain a characterization of all finite affine spaces of dimension at least 3 with lines of size at least 3.     

Countable compact Hausdorff spaces need not be metrizable in ZF

We show that the existence of a countable, first countable, zero-dimensional, compact Hausdorff space which is not second countable, hence not metrizable, is consistent with ZF.

     

Corrigendum to “Characterization of Sobolev and BV spaces” [J. Funct. Anal. 261 (10) (2011) 2926–2958]

We correct a mistake in [3].     

The classical Banach spaces

In this paper we study some structural and geometric properties of the quotient Banach spaces , where is an arbitrary set, is an Orlicz function, is the corresponding Orlicz space on and , being the ideal of elements with finite support. The results we obtain here extend and complete the ones obtained by Leonard and Whitfield (Rocky Mountain J. Math. 13 (1983), 531-539). We show that is not a dual space, that , if for every , that has no smooth points, that it cannot be renormed equivalently with a strictly convex or smooth norm, that is a Grothendieck space, etc.

     

初始的L-外部空间

研究了初始的L-外部空间.构造了L-外部空间范畴的初始结构,并由此定义了L-外部空间的乘积结构和子空间结构,证明了L-外部空间范畴是L-预外部空间范畴的余反射子范畴.     

关于rectifiable空间中的局部(序列)连通性的几个注记

给出连通的rectifiable空间是局部序列连通(或局部连通)的刻画,推广了拓扑群中的相应结果;利用rectifiable空间G中e的局部邻域基给出G是局部连通(或局部序列连通)的刻画;证明了若A是rectifiable空间G中的序列开子集,那么H=A是G的序列开rectifiable子空间.     

Higher-order symmetrization inequalities and applications

We prove new extended forms of the Pólya-Szegö symmetrization principle. As a consequence new sharp embedding theorems for generalized Sobolev and Besov spaces are proved.     

Symmetrization inequalities in the fractional case and Besov embeddings

We prove new extended forms of the Pólya-Szegö symmetrization principle in the fractional case. As a consequence we determine new results for rearrangement invariant hulls of generalized Besov spaces.     

Completeness of quasi-normed symmetric operator spaces

We show that (generalized) Calkin correspondence between quasi-normed symmetric sequence spaces and symmetrically quasi-normed ideals of compact operators on an infinite-dimensional Hilbert space preserves completeness. We also establish a semifinite version of this result.