排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Mircea Martin 《Proceedings of the American Mathematical Society》2002,130(10):2971-2983
Three natural multi-dimensional substitutes for the self-commutator of a Hilbert space operator are introduced and generalizations of Putnam's inequality to tuples of operators with semidefinite self-commutators are indicated. In addition, a Riesz transform model is developed and investigated.
2.
Reflexivity of Operator Weighted Shifts 总被引:1,自引:0,他引:1
Li Juexian 《东北数学》1995,(4)
ReflexivityofOperatorWeightedShiftsLiJuexian(李觉先)(DepartmentofMathematics,LiaoningUniversity,Shengyang,110036)ZhaoTianxia(赵天霞... 相似文献
3.
The problem whether Aluthge iteration of bounded operators on a Hilbert space H is convergent was introduced in [I. Jung, E. Ko, C. Pearcy, Aluthge transforms of operators, Integral Equations Operator Theory 37 (2000) 437-448]. And the problem whether the hyponormal operators on H with dimH=∞ has a convergent Aluthge iteration under the strong operator topology remains an open problem [I. Jung, E. Ko, C. Pearcy, The iterated Aluthge transform of an operator, Integral Equations Operator Theory 45 (2003) 375-387]. In this note we consider symbols with a fractional monotone property which generalizes hyponormality and 2-expansivity on weighted translation semigroups, and prove that if {St} is a weighted translation semigroup whose symbol has the fractional monotone property, then its Aluthge iteration converges to a quasinormal operator under the strong operator topology. 相似文献
4.
Rebecca Sanders 《Journal of Mathematical Analysis and Applications》2004,292(1):148-159
Inspired by a recent result that a weakly hypercyclic operator may fail to be norm hypercyclic, we show there exists a weakly supercyclic operator that fails to be norm supercyclic. Moreover, despite a classical result of Hilden and Wallen that every unilateral weighted backward shift is supercyclic, we show such an operator may have a weakly supercyclic vector that is not a norm supercyclic vector. In addition to these results, we extend a result of Kitai by showing a hyponormal operator cannot be weakly hypercyclic. 相似文献
5.
In this paper it is shown that if T∈L(H) satisfies
- (i)
- T is a pure hyponormal operator;
- (ii)
- [T∗,T] is of rank two; and
- (iii)
- ker[T∗,T] is invariant for T,
6.
In this article, we give a new proof of the Carey–Helton–Howe–Pincus trace formula using Kato's theory of “relatively-smooth” operators and Krein's trace formula. 相似文献
7.
Dragan S. Djordjevi? 《Journal of Mathematical Analysis and Applications》2007,329(2):1181-1190
In this paper normal and hyponormal operators with closed ranges, as well as EP operators, are characterized in arbitrary Hilbert spaces. All characterizations involve generalized inverses. Thus, recent results of S. Cheng and Y. Tian [S. Cheng, Y. Tian, Two sets of new characterizations for normal and EP matrices, Linear Algebra Appl. 375 (2003) 181-195] are extended to infinite-dimensional settings. 相似文献
8.
Bebe Prunaru 《Proceedings of the American Mathematical Society》1996,124(11):3411-3412
Let be a pure hyponormal operator with compact self-commutator. We show that the unit ball of the commutant of is compact in the strong operator topology.
9.
Bebe Prunaru 《Proceedings of the American Mathematical Society》1997,125(6):1689-1691
We show that if is a bounded operator on a Hilbert space such that for every polynomial , then has a nontrivial invariant subspace.
10.
In Sung Hwang 《Journal of Mathematical Analysis and Applications》2011,382(2):883-891
This paper concerns a gap between hyponormality and subnormality for block Toeplitz operators. We show that there is no gap between 2-hyponormality and subnormality for a certain class of trigonometric block Toeplitz operators (e.g., its co-analytic outer coefficient is invertible). In addition we consider the extremal cases for the hyponormality of trigonometric block Toeplitz operators: in this case, hyponormality and normality coincide. 相似文献