The role of BMOA in the boundedness of weighted composition operators on the unit ball

We study the weighted composition operators Wh,on Hardy space H2(B) whenever h ∈ BMOA(resp.h ∈ VMOA).Analogous results are given for Hp(B) spaces and the scale of weighted Bergman spaces.In the latter case,BMOA is replaced by the Bloch space(resp.VMOA by the little Bloch space).     

BMOA空间的一个特征

对于单位圆盘上的BMOA(有界平均振动解析函数)空间已经有了许多重要的工作.通常所见的是考虑BMOA函数的一阶导数在单位圆盘上的某种积分性质.本文证明了可以用BMOA函数的任意导数来刻划BMOA函数的性质.从而也推广了BMOA函数的一个熟知的特征.     

The Equivalence of BMOA and VMOA on the Unit Ball of C n

１ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔＢｂｅｔｈｅｏｐｅｎｕｎｉｔｂａｌｉｎＣｎａｎｄＳｂｅｉｔｓｂｏｕｎｄａｒｙ．ＬｅｔσｂｅｔｈｅｒｏｔａｔｉｏｎｉｎｖａｒｉａｎｔｐｒｏｂａｂｉｌｉｔｙｍｅａｓｕｒｅｏｎＳ．Ｆｏｒζ∈Ｓａｎｄδ＞０,ｌｅｔＱ（ζ,δ）...     

BMOA中泰勒系数为正的函数的特征

本文用较简单的方法证明了Fefferman, C.的一个结果.同时我们还得到了使了BMOA的一个较弱的充分条件.     

The role of BMOA in the boundedness of weighted composition operators

Boundedness (resp. compactness) of weighted composition operators Wh,φ acting on the classical Hardy space H² as Wh,φf=h(f○φ) are characterized in terms of a Nevanlinna counting function associated to the symbols h and φ whenever h∈BMOA (resp. h∈VMOA). Analogous results are given for Hp spaces and the scale of weighted Bergman spaces. In the latter case, BMOA is replaced by the Bloch space (resp. VMOA by the little Bloch space).     

BMOA与VMOA上复合算子的紧性

本文给出了BMOA空间上复合算子为紧的一个新的而且简单的充要条件，原有的条件不仅繁杂而且没有操作性。利用我们的新结果很容易地得到     

Compactness of composition operators on BMOA and VMOA

We give a new and simple compactness condition for composition operators on BMOA,the space of all analytic functions of the bounded mean oscillation on the unit disk.Using our results one may immediately obtain that compactness of a composition operator on BMOA implies its compactness on the Bloch space as well as on the Hardy space.Similar results on VMOA are also given.