摘要
称有界线性算子T满足(ω_1)性质,如果T的上半Weyl谱在它的逼近点谱中的补集包含在它的谱集中孤立的有限重的特征值的全体中。根据单值扩张性质定义了一种新的谱集,利用该谱集给出了Hilbert空间中有界线性算子满足(ω_1)性质的充分必要条件。作为应用,给出了亚(或超)循环算子类满足(ω_1)性质的等价刻画。
A bounded linear operator T satisfies property(ω_1), if the complement in the approximate point spectrum σ_a(T) of the upper semi-Weyl spectrum σ_(ea)(T) is contained in the set of all isolated points of the spectrum σ(T) which are finite eigenvalues. In this paper, by means of the new spectrum defined in view of the single-valued extension property, the sufficient and necessary conditions for a bounded linear operator defined on a Hilbert space satisfying the property(ω_1) are established. As an application, the property(ω_1) for hypercyclic(or supercyclic) operators are characterised.
引文
[1]WEYL H.Uber beschrankte quadratische formen,deren differenz vollstetig ist[J].Rendiconti Del Circolo Matematico Di Palermo,1909,27(1):373-392.
[2]RAKOCEVIC V.On a class of operators[J].Matematicki Vesnik,1985,37(4):423-426.
[3]RAKOCEVIC V.Operators obeying a-Weyls theorem[J].Romanian Journal of Pure and Applied Mathematics,1989,34(10):915-919.
[4]BERKANI M,KOLIHA J J.Weyl type theorems for bounded linear operators[J].Acta Scientiarum Mathematicarum,2003,69(1):359-376.
[5]SUN Chenhui,CAO Xiaohong,DAI Lei.Property(ω1)and Weyl type theorem[J].Journal of Mathematical Analysis and Applications,2010,363(1):1-6.
[6]ZENG Qingping,ZHONG Huaijie.A note on property(gb)and perturbations[J].Abstract and Applied Analysis,2012,72(1):1-16.
[7]DUNFORD N.Spectral theory II:resolution of the identity[J].Pacific Journal of Mathematics,1952,2(4):559-614.
[8]LAURSEN K B,NEUMANN M M.An introduction to local spectral theory[M].Oxford:Clarendon Press,2000.
[9]AMOUCH A.Weyl type theorems for operators satisfying the single-valued extension property[J].Journal of Mathematical Analysis and Applications,2007,326(2):1476-1484.
[10]OUDGHIRI M.A-Weyls theorem and the single valued extension property[J].Extracta Mathematicae,2006,21(1):41-50.
[11]戴磊,曹小红.单值延拓性质与广义(ω)性质[J].陕西师范大学学报(自然科学版),2011,39(2):17-22.DAI Lei,CAO Xiaohong.The single valued extension property and generalized property(ω)[J].Journal of Shaanxi Normal U-niversity(Natural Science Edition),2011,39(2):17-22.
[12]CONWAY J B.A course in functional analysis[M].New York:Springer-Verlag,2003:181-182.
[13]KITAI C.Invariant closed sets for linear operators[D].Toronto:University of Toronto,1982.
[14]HERRERO D.Limits of hypercyclic and supercyclic operators[J].Journal of Functional Analysis,1991,99(1):179-190.