• Journal of applied mathematics & informatics
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• 제3권2호
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• pp.117-128
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• 1996

Complementation theory in krein spaces can be extended for any self-adjoint transformation. There is a close relation between Julia operators and linear systems. The theory of Julia operators can be used to construct distinct Krein spaces which are the state spaces of extended canonical linear systems with given transfer function.

• Korean Journal of Mathematics
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• 제10권2호
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• pp.103-116
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• 2002

We characterize operators between Banach spaces sending compact sets into sets that lie in the range of a vector measure. Further, we describe operators between Banach spaces taking compact sets into sets that lie in the range of a vector measure of bounded variation.

• 대한수학회보
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• 제37권3호
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• pp.437-450
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• 2000

On the setting of the half-plane H={x+iy$\mid$y>0} of the complex plane, we study some properties of weighted Bergman spaces and their duality. We also obtain some characterizations of compact Toeplitz operators.

• 대한수학회지
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• 제50권1호
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• pp.137-159
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• 2013

It is studied the linear combinations of composition operators on the Banach space of bounded harmonic functions on the open unit disk. We determine the essential norm of them.

• Korean Journal of Mathematics
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• 제23권3호
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• pp.447-456
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• 2015

In this paper we show that some operators defined on the Banach space with an unconditional basis and $L^1({\mu})$ into a Banach space with the RNP have liftable operators.

• 대한수학회보
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• 제32권2호
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• pp.205-209
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• 1995

Throughout this paper X is a Banach space and $\mu$ is the Lebesgue measure on [0, 1] and all operators are assumed to be bounded and linear. $L^1(\mu)$ is the Banach space of all (classes of) Lebesgue integrable functions on [0, 1] with its usual norm. Let $T : L^1(\mu) \to X$ be an operator.

• 대한수학회보
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• 제36권1호
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• pp.131-138
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• 1999

We consider the Boolean linear operators that preserve Boolean rank and obtain some characterizations of the linear operators which extend the results in [1].

• 대한수학회보
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• 제57권2호
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• pp.509-520
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• 2020

We study the Toeplitz operators on the holomorphic and pluriharmonic Dirichlet spaces of the polydisk in terms of when Toeplitz operator is Fredholm operator there. Consequently, we describe the essential spectrum of Toeplitz operators.

• Kyungpook Mathematical Journal
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• 제47권2호
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• pp.253-265
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• 2007

In this paper, the boundedness for some multilinear operators generated by singular integralv operators and Lipschitz functions on Hardy and Herz-type spaces are obtained.

• 호남수학학술지
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• 제39권2호
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• pp.175-185
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• 2017

In this paper we consider Toeplitz operators on the pluriharmonic Dirichlet space of the unit ball in the n-dimensional complex space. We then characterize Fredholm Toeplitz operators and describe the essential spectrum of a Toeplitz operator as a consequence.