共查询到20条相似文献,搜索用时 15 毫秒
1.
On the Dirichlet space of the unit disk, we consider operators that are finite sums of Toeplitz products, Hankel products
or products of a Toeplitz operator and a Hankel operator. We characterize when such operators are equal to zero. Our results
extend several known results using completely different arguments. 相似文献
2.
Victor M. Adukov 《Linear algebra and its applications》1999,290(1-3):119-134
The goal of the paper is a generalized inversion of finite rank Hankel operators and Hankel or Toeplitz operators with block matrices having finitely many rows. To attain it a left coprime fractional factorization of a strictly proper rational matrix function and the Bezout equation are used. Generalized inverses of these operators and generating functions for the inverses are explicitly constructed in terms of the fractional factorization. 相似文献
3.
In this paper, we study some algebraic properties of Toeplitz operators with quasihomogeneous symbols on the Dirichlet space of the unit ball Bn. First, we describe commutators of a radial Toeplitz operator and characterize commuting Toeplitz operators with quasihomogeneous symbols. Then we show that finite raak product of such operators only happens in the trivial case. Finally, some necessary and sufficient conditions are given for the product of two quasihomogeneous Toeplitz operators to be a quasihomogeneous Toeplitz operator. 相似文献
4.
Richard Rochberg 《Integral Equations and Operator Theory》1987,10(2):187-235
The basic theory of Toeplitz and Hankel operators acting on the Paley-Weiner space is developed. This includes criteria for boundedness, compactness, being of finite rank, and membership in the Schatten-von Neumann ideals. Similar questions are considered for the related operators formed by commuting the discrete Hilbert transform with a multiplication operator.Supported in part by a grant from the National Science Foundation. 相似文献
5.
若S是Dirichlet空间上有限个Toeplitz算子乘积的有限和, S为紧算子的充要条件是: 当z→∂D时, S的Berezin型变换收敛到0; 若S是Dirichlet空间上Hankel算子, S为紧算子的充要条件是: 当z→ D时, S作用在类再生核上按范数收敛到0. 相似文献
6.
Tao Yu 《Integral Equations and Operator Theory》2010,67(2):163-170
In this paper a decomposition of Sobolev space is obtained. Then we prove that a Toeplitz operator on the Dirichlet space
is compact only when it is the zero operator. For two Toeplitz operators on the Dirichlet space, we obtain the conditions
for that they commute, their product is a Toeplitz operator, and their commutator or semi-commutator has finite rank, respectively. 相似文献
7.
In this paper,we discuss some algebraic properties of Toeplitz operators and small Hankel operators with radial and quasihomogeneous symbols on the harmonic Bergman space of the unit disk in the complex plane C.We solve the product problem of quasihomogeneous Toeplitz operator and quasihomogeneous small Hankel operator.Meanwhile,we characterize the commutativity of quasihomogeneous Toeplitz operator and quasihomogeneous small Hankel operator. 相似文献
8.
9.
Namita Das 《印度理论与应用数学杂志》2010,41(2):379-400
In this paper the concept of asymptotic Toeplitz and asymptotic Hankel operators on the Bergman space are introduced and properties of these classes of operators are studied. The importance of this notion is that it associates with a class of operators a Toeplitz operator and with a class of operators a Hankel operator where the original operators are not even Toeplitz or Hankel. Thus it is possible to assign a symbol to an operator that is not Toeplitz or Hankel and hence a symbol calculus is obtained. Further a relation between Toeplitz operators and little Hankel operators on the Bergman space is established in some asymptotic sense. 相似文献
10.
We study three different problems in the area of Toeplitz operators on the Segal-Bargmann space in Cn. Extending results obtained previously by the first author and Y.L. Lee, and by the second author, we first determine the commutant of a given Toeplitz operator with a radial symbol belonging to the class Sym>0(Cn) of symbols having certain growth at infinity. We then provide explicit examples of zero-products of non-trivial Toeplitz operators. These examples show the essential difference between Toeplitz operators on the Segal-Bargmann space and on the Bergman space over the unit ball. Finally, we discuss the “finite rank problem”. We show that there are no non-trivial rank one Toeplitz operators Tf for f∈Sym>0(Cn). In all these problems, the growth at infinity of the symbols plays a crucial role. 相似文献
11.
Kunyu Guo 《Journal of Functional Analysis》2003,201(1):121-147
We characterize when a Hankel operator and a Toeplitz operator have a compact commutator. 相似文献
12.
Young Joo Lee 《Journal of Mathematical Analysis and Applications》2009,357(2):504-515
On the Dirichlet space of the unit disk, we consider a class of operators which contain finite sums of products of two Toeplitz operators with harmonic symbols. We give characterizations of when an operator in that class is zero or compact. Also, we solve the zero product problem for products of finitely many Toeplitz operators with harmonic symbols. 相似文献
13.
Using the C? algebraic scattering approach to study quasifree fermionic systems out of equilibrium in quantum statistical mechanics, we construct the nonequilibrium steady state in the isotropic XY chain whose translation invariance has been broken by a local magnetization and analyze the asymptotic behavior of the expectation value for a class of spatial correlation observables in this state. The effect of the breaking of translation invariance is twofold. Mathematically, the finite rank perturbation not only regularizes the scalar symbol of the invertible Toeplitz operator generating the leading order exponential decay but also gives rise to an additional trace class Hankel operator in the correlation determinant. Physically, in its decay rate, the nonequilibrium steady state exhibits a left mover-right mover structure affected by the scattering at the impurity. 相似文献
14.
On the Bergman space of the unit polydisk, we study a class of operators which contains sums of finitely many Toeplitz products
with pluriharmonic symbols. We give characterizations of when an operator in that class has finite rank or is compact. As
one of applications we show that sums of a certain number, depending on and increasing with the dimension, of semicommutators
of Toeplitz operators with pluriharmonic symbols cannot be compact without being the zero operator. 相似文献
15.
In this paper we completely characterize compact Toeplitz operators on the harmonic Bergman space. By using this result we establish the short exact sequences associated with the Toeplitz algebra and the Hankel algebra. We show that the Fredholm index of each Fredholm operator in the Toeplitz algebra or the Hankel algebra is zero. 相似文献
16.
In 1997 Ptak defined generalized Hankel operators as follows: Given two contractions
and
, an operator
is said to be a generalized Hankel operator if
and X satisfies a boundedness condition that depends on the unitary parts of the minimal isometric dilations of T
1 and T
2. This approach, call it (P), contrasts with a previous one developed by Ptak and Vrbova in 1988, call it (PV), based on the existence of a previously defined generalized Toeplitz operator. There seemed to be a strong but somewhat hidden connection between the theories (P) and (PV) and we clarify that connection by proving that (P) is more general than (PV), even strictly more general for some T
1 and T
2, and by studying when they coincide. Then we characterize the existence of Hankel operators, Hankel symbols and analytic Hankel symbols, solving in this way some open problems proposed by Ptak. 相似文献
17.
Lova Zakariasy 《Proceedings of the American Mathematical Society》2003,131(4):1177-1180
We show that on the harmonic Bergman spaces, the Hankel operators with nonconstant harmonic symbol cannot be of finite rank.
18.
In this paper, we characterize when the Toeplitz operator Tf and the Hankel operator Hg commute on the Hardy space of the bidisk. For certain types of bounded symbols f and g, we give a necessary and sufficient condition on the symbols to guarantee TfHg = HgTf. 相似文献
19.
In this paper we characterize commuting dual Toeplitz operators with harmonic symbols on the orthogonal complement of the Dirichlet space in the Sobolev space. We also obtain the sufficient and necessary conditions for the product of two dual Toeplitz operators with harmonic symbols to be a finite rank perturbation of a dual Toeplitz operator. 相似文献
20.
Boo Rim Choe 《Journal of Mathematical Analysis and Applications》2011,381(1):365-382
On the Hardy space over the unit ball in Cn, we consider operators which have the form of a finite sum of products of several Toeplitz operators. We study characterizing problems of when such an operator is compact or of finite rank. Some of our results show higher-dimensional phenomena. 相似文献