侯曉陽,許 毅,陳 偉
(1.溫州商學院基礎部,浙江溫州 325035;2.溫州大學數(shù)理與電子信息工程學院,浙江溫州 325035)
若n=0,則就是加權復合算子,如果再有u(z)≡1,則為復合算子Cφ.
Madigan K和Matheson A在文[2]中研究了Bloch空間和小Bloch空間上復合算子Cφ的有界性和緊性問題;LouZ[3]研究了不同權Bloch型空間之間的復合算子Cφ,對于H∞空間上的加權復合算子uCφ的有關結論,可見文[4-8]及相應文獻;Stevic[9-10]和劉永民等[11]等研究了混合范數(shù)空間和Bloch空間,以及Hardy空間上的加權微分復合算子的有界性和緊性問題.文獻[12]研究了單位圓盤上從BMOA空間到Bloch型空間的加權微分復合算子的有界性和緊性,得到:
當α=1時,即為上述定理A,定理B;當n=1,時,則算子,可得文[13]主要結論:
定理的證明主要采用待定系數(shù)法確定檢驗函數(shù),本文出現(xiàn)的字母C表示與變量z,w等無關的常數(shù),為方便起見,不同的地方可以表示不同的常數(shù).
引理1 對任意正整數(shù)n,f∈Bα,存在常數(shù)C(只與權值α有關),使得
引理1可見文[14]定理5的證明過程,下面的緊性判斷引理見文[15]定理3.11,取X=Bα,Y=Bβ,類似證明可得.
定理1的證明:充分性.若條件(1)(2)成立,結合引理1,可得:
綜合(8)和(9)可知(1)式成立.
定理2的證明:充分性.對Bα中的任意有界序列,有fk在D的緊子集上一致收斂于0,由引理2,只需證明.以下不妨設
由條件(3)和(4),?ε>0,當時,有:
結合(10)和(11)式,以及引理1,可得:
當|z|≤r<1時,有:
即fk(z)在D的緊子集上一致收斂于0.故由引理2,結合式(14)式得到:
[1] Zhu X L. Products of differentiation, composition and multiplication from Bergman type spaces to Bers type spaces[J]. Integr Transf Spec F, 2007, 18(3/4):223-231.
[2] Madigan K, Matheson A. Compact composition operators on the Bloch space [J]. Trans Amer Math Soc, 1995, 347:2679-2687.
[3] Lou Z. Composition operators on Bloch type spaces [J]. Analysis, 2003, 1(1):81-95.
[4] Shi J H, Luo L. Composition operators on the Bloch space of several complex variables [J]. Acta Math Sin, 2000, 16:85-98.
[5] Ohno S, Zhao R H. Weighted composition operators on the Bloch space [J]. Bull Austral Math Soc, 2001, 63:177-185.
[6] Ohno S. Weighted composition operators betweenH∞and the Bloch space [J]. Taiwanese J Math , 2006, 5(3):555-563.
[7] Colonna F. Weighted composition operators betweenH∞and BMOA [J]. Bull Korean Math Soc, 2013, 50(1):185-200.
[8] 劉超,侯曉陽.Besov空間到Zygmund空間上的加權復合算子[J].純粹數(shù)學與應用數(shù)學,2016,32(2):197-205.
[9] Stevic S. Weighted differentiation composition operators from mixed-norm spaces to weighted-type spaces [J]. App Math Comput, 2009, 211(1):222-233.
[10] Stevic S. Weighted differentiation composition operators fromH∞and Bloch spaces to nth weighted-type spaces on the unit disk [J]. App Math Comput, 2010, 216(2):3634-3641.
[11] 劉永民,于燕燕.從Hardy空間到Zygmund-型空間的加權微分復合算子[J].數(shù)學年刊A輯,2014,35(4):399-412.
[12] Liu J, Lou Z, Sharama A. Weighted differentiation composition operators to Bloch-type spaces [J]. Abstr Appl Anal,2013(1):233-255.
[13] Li S, Stevic S. Composition followed by differentiation between Bloch-type spaces [J]. J Comput Anal Appl, 2007,9(2):195-206.
[14] Zhu K. Bloch type spaces of analytic functions [J]. Rock Mou J Math, 1993, 23(3):1143-1177.
[15] Cowen C, Maccluer B. Composition operators on spaces of analytic functions [M]. Florida:CRC Press, 1995:128-129.