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1.
We prove analogues of the Brown-Halmos and Nehari theorems on
the norms of Toeplitz and Hankel operators, respectively, acting on subspaces
of Hardy type of reflexive rearrangement-invariant spaces with nontrivial Boyd
indices. 相似文献
2.
A well known lemma attributed to Coburn states that a Toeplitz operator with non-trivial kernel acting on the Hardy space must have dense range. We show that the range of a non-zero Toeplitz operator with non-trivial kernel must contain all polynomials and state this in a precise form. 相似文献
3.
Maribel Loaiza Marcos López-García Salvador Pérez-Esteva 《Integral Equations and Operator Theory》2005,53(2):287-296
In this paper we decompose
into diadic annuli
and consider the class Sp,q of Toeplitz operators Tφ for which the sequence of Schatten norms
belongs to ℓq, where φn = φχ An. We study the boundedness and compactness of the operators in Sp,q and we describe the operators Tφ , φ ≥ 0 in these spaces in terms of weighted Herz norms of the averaging operator of the symbols φ. 相似文献
4.
We characterize complex measures μ on the unit disk for which the Toeplitz operator T
μ
is bounded or compact on the analytic Besov spaces B
p
with 1 ≤ p < ∞.
Research supported in part by NSF grant, DMS 0200587 (first author); and by a NSERC grant (third author). 相似文献
5.
We consider large finite Toeplitz matrices with symbols of the form (1– cos )p f() where p is a natural number and f is a sufficiently smooth positive function. By employing techniques based on the use of predictor polynomials, we derive exact and asymptotic formulas for the entries of the inverses of these matrices. We show in particular that asymptotically the inverse matrix mimics the Green kernel of a boundary value problem for the differential operator
Submitted: June 20, 2003 相似文献
6.
Rambour and Seghier established two deep results on the first order asymptotics of the entries of the inverses of certain Toeplitz matrices. The determination of the constants in the leading terms of the asymptotics turns out to be nontrivial. We here show how these constants can be obtained from a well known identity by Duduchava and Roch.Submitted: October 20, 2003 相似文献
7.
Products of Toeplitz Operators on the Bergman Space 总被引:1,自引:0,他引:1
Issam Louhichi Elizabeth Strouse Lova Zakariasy 《Integral Equations and Operator Theory》2006,54(4):525-539
In 1962 Brown and Halmos gave simple conditions for the product of two Toeplitz operators on Hardy space to be equal to a
Toeplitz operator. Recently, Ahern and Cucković showed that a similar result holds for Toeplitz operators with bounded harmonic
symbols on Bergman space. For general symbols, the situation is much more complicated. We give necessary and sufficient conditions
for the product to be a Toeplitz operator (Theorem 6.1), an explicit formula for the symbol of the product in certain cases
(Theorem 6.4), and then show that almost anything can happen (Theorem 6.7). 相似文献
8.
Nathan S. Feldman 《Integral Equations and Operator Theory》2007,58(2):153-173
A pair of commuting operators, (A,B), on a Hilbert space
is said to be hypercyclic if there exists a vector
such that {A
n
B
k
x : n, k ≥ 0} is dense in
. If f, g ∈H
∞(G) where G is an open set with finitely many components in the complex plane, then we show that the pair (M
*
f
, M
*
g
) of adjoints of multiplcation operators on a Hilbert space of analytic functions on G is hypercyclic if and only if the semigroup they generate contains a hypercyclic operator. However, if G has infinitely many components, then we show that there exists f, g ∈H
∞(G) such that the pair (M
*
f
, M
*
g
) is hypercyclic but the semigroup they generate does not contain a hypercyclic operator. We also consider hypercyclic n-tuples. 相似文献
9.
In the case of radial symbols we study the behavior of different properties (boundedness, compactness, spectral properties, etc.) of Toeplitz operators Ta() acting on weighted Bergman spaces
over the unit disk
, in dependence on , and compare their limit behavior under
with corresponding properties of the initial symbol a. 相似文献
10.
Let D be a bounded logarithmically convex complete Reinhardt domain in
centered at the origin. Generalizing a result for the one-dimensional case of the unit disk, we prove that the C
*-algebra generated by Toeplitz operators with bounded measurable separately radial symbols (i.e., symbols depending only on
is commutative.
We show that the natural action of the n-dimensional torus
defines (on a certain open full measure subset of D) a foliation which carries a transverse Riemannian structure having distinguished geometric features. Its leaves are equidistant
with respect to the Bergman metric, and the orthogonal complement to the tangent bundle of such leaves is integrable to a
totally geodesic foliation. Furthermore, these two foliations are proved to be Lagrangian.
We specify then the obtained results for the unit ball. 相似文献
11.
Željko Čučković 《Integral Equations and Operator Theory》2007,59(3):345-353
We study finite rank perturbations of the Brown-Halmos type results involving products of Toeplitz operators acting on the
Bergman space.
相似文献
12.
Extending known results for the unit disk, we prove that for the unit ball there exist n+2 different cases of commutative C*-algebras generated by Toeplitz operators, acting on weighted Bergman spaces. In all cases the bounded measurable symbols
of Toeplitz operators are invariant under the action of certain commutative subgroups of biholomorphisms of the unit ball.
This work was partially supported by CONACYT Projects 46936 and 44620, México. 相似文献
13.
On the Bergman space of the unit polydisk in the complex n-space, we solve the zero-product problem for two Toeplitz operators with n-harmonic symbols that have local continuous extension property up to the distinguished boundary. In the case where symbols
have additional Lipschitz continuity up to the whole distinguished boundary, we solve the zero-product problem for products
with four factors. We also prove a local version of this result for products with three factors. 相似文献
14.
We study the commuting problem for Toeplitz operators on the harmonic Bergman space of the unit disk. We show that an analytic Toeplitz operator and a co-analytic Toeplitz operator with certain noncyclicity hypothesis can commute only when one of their symbols is constant. We also obtain analogous results for semi-commutants. 相似文献
15.
Essential Norms of Composition Operators 总被引:2,自引:0,他引:2
We obtain simple estimates for the essential norm of a composition
operator acting from the Hardy space H
p
to H
q
, p > q, in one or several
variables. When p = and q = 2 our results give an exact formula for the
essential norm. 相似文献
16.
Trieu Le 《Integral Equations and Operator Theory》2007,59(4):555-578
Using the joint local mean oscillation, Jingbo Xia [13] showed that the essential commutant of , where is the subalgebra of L
∞ generated by all functions which are bounded and have at most one discontinuity, is (QC). Even though Xia’s method cannot be used, we are able to generalize his result to Toeplitz operators in higher dimensions
with a different approach. This result is stronger than the well-known result stating that the essential commutant of the
full Toeplitz algebra is (QC).
相似文献
17.
Motivated by recent works of Ahern and uković on the disk, we study the generalized zero product problem for Toeplitz operators acting on the Bergman space of the polydisk. First, we extend the results to the polydisk. Next, we study the generalized compact product problem. Our results are new even on the disk. As a consequence on higher dimensional polydisks, we show that the generalized zero and compact product properties are the same for Toeplitz operators in a certain case.The first three authors were partially supported by KOSEF(R01-2003-000-10243-0) and the last author was partially supported by the National Science Foundation. 相似文献
18.
David Cruz-Uribe 《Integral Equations and Operator Theory》1994,20(2):231-237
In this note I give necessary and sufficient conditions on outer functionsf andg for the operator
to be bounded and invertible on H2. I also discuss the relationship of this question to two open questions in operator theory and weighted norm inequalities. 相似文献
19.
We prove a formula expressing a generaln byn Toeplitz determinant as a Fredholm determinant of an operator 1 –K acting onl
2
(n,n+1,...), where the kernelK admits an integral representation in terms of the symbol of the original Toeplitz matrix. The proof is based on the results of one of the authors, see [14], and a formula due to Gessel which expands any Toeplitz determinant into a series of Schur functions. We also consider 3 examples where the kernel involves the Gauss hypergeometric function and its degenerations. 相似文献
20.
Raúl E. Curto Sang Hoon Lee Woo Young Lee 《Integral Equations and Operator Theory》2002,44(2):138-148
In this article we provide an example of a Toeplitz operator which is 2-hyponormal but not subnormal, and we consider 2-hyponormal Toeplitz operators with finite rank self-commutators.Supported by NSF research grant DMS-9800931.Supported by KOSEF research project No. R01-2000-00003. 相似文献