scholarly journals Pseudo-B-Fredholm operators, poles of the resolvent and mean convergence in the calkin algebra

Filomat ◽  
2019 ◽  
Vol 33 (11) ◽  
pp. 3351-3359
Author(s):  
Mohammed Berkani ◽  
Snezana Zivkovic-Zlatanovic
Keyword(s):  
Compact Operator ◽  
Essential Spectrum ◽  
Fredholm Operator ◽  
Fredholm Operators ◽  
Riesz Operator ◽  
Calkin Algebra ◽  
Mean Convergence ◽  
The Mean

We define here a pseudo B-Fredholm operator as an operator such that 0 is isolated in its essential spectrum, then we prove that an operator T is pseudo-B-Fredholm if and only if T = R + F where R is a Riesz operator and F is a B-Fredholm operator such that the commutator [R,F] is compact. Moreover, we prove that 0 is a pole of the resolvent of an operator T in the Calkin algebra if and only if T = K + F, where K is a power compact operator and F is a B-Fredholm operator, such that the commutator [K,F] is compact. As an application, we characterize the mean convergence in the Calkin algebra.

scholarly journals Some special characterisations of Fredholm operators in Banach space

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 169-174
Author(s):  
Mahendra Shahi
Keyword(s):  
Banach Space ◽  
Linear Operator ◽  
Essential Spectrum ◽  
Fredholm Operator ◽  
Bounded Linear Operator ◽  
Global Analysis ◽  
Spectral Theorem ◽  
Bounded Operators ◽  
Fredholm Operators ◽  
Bounded Linear

A bounded linear operator which has a finite index and which is defined on a Banach space is often referred to in the literature as a Fredholm operator. Fredholm operators are important for a variety of reasons, one being the role that their index plays in global analysis. The aim of this paper is to prove the spectral theorem for compact operators in refined form and to describe some properties of the essential spectrum of general bounded operators by the use of the theorem of Fredholm operators. For this, we have analysed the Fredholm operator which is defined in a Banach space for some special characterisations. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10399 BIBECHANA 11(1) (2014) 169-174

The Mean Convergence of Orthogonal Series

1950 ◽  
Vol 72 (4) ◽  
pp. 792 ◽  
Author(s):  
G. Milton Wing
Keyword(s):  
Orthogonal Series ◽  
Mean Convergence ◽  
The Mean

CERTAIN ISOMETRIES RELATED TO THE BILATERAL LAPLACE TRANSFORM

2006 ◽  
Vol 11 (3) ◽  
pp. 331-346 ◽  
Author(s):  
S. B. Yakubovich
Keyword(s):  
Hilbert Space ◽  
Entire Function ◽  
Laplace Transform ◽  
Hilbert Spaces ◽  
Reproducing Kernel ◽  
Reproducing Kernel Hilbert Space ◽  
Inversion Formulas ◽  
Mean Convergence ◽  
The Laplace Transform ◽  
The Mean

We study certain isometries between Hilbert spaces, which are generated by the bilateral Laplace transform In particular, we construct an analog of the Bargmann‐Fock type reproducing kernel Hilbert space related to this transformation. It is shown that under some integra‐bility conditions on $ the Laplace transform FF(z), z = x + iy is an entire function belonging to this space. The corresponding isometrical identities, representations of norms, analogs of the Paley‐Wiener and Plancherel's theorems are established. As an application this approach drives us to a different type of real inversion formulas for the bilateral Laplace transform in the mean convergence sense.

On the mean convergence of Fourier–Jacobi series

2010 ◽  
Vol 62 (6) ◽  
pp. 943-960 ◽  
Author(s):  
V. P. Motornyi ◽  
S. V. Goncharov ◽  
P. K. Nitiema
Keyword(s):  
Jacobi Series ◽  
Mean Convergence ◽  
The Mean

scholarly journals Non-weak compactness of the integration map for vector measures

1993 ◽  
Vol 54 (3) ◽  
pp. 287-303 ◽  
Author(s):  
S. Okada ◽  
W. J. Ricker
Keyword(s):  
Banach Space ◽  
Volterra Operator ◽  
Continuous Operator ◽  
Weakly Compact ◽  
Vector Measures ◽  
Mean Convergence ◽  
Integrable Functions ◽  
The Mean ◽  
The Fourier Transform ◽  
Adjoint Operators

AbstractLet m be a vector measure with values in a Banach space X. If L1(m) denotes the space of all m integrable functions then, with respect to the mean convergence topology, L1(m) is a Banach space. A natural operator associated with m is its integration map Im which sends each f of L1(m) to the element ∫fdm (of X). Many properties of the (continuous) operator Im are closely related to the nature of the space L1(m). In general, it is difficult to identify L1(m). We aim to exhibit non-trivial examples of measures m in (non-reflexive) spaces X for which L1(m) can be explicitly computed and such that Im is not weakly compact. The examples include some well known operators from analysis (the Fourier transform on L1 ([−π, π]), the Volterra operator on L1 ([0, 1]), compact self-adjoint operators in a Hilbert space); such operators can be identified with integration maps Im (or their restrictions) for suitable measures m.

scholarly journals On the Mean Convergence

1930 ◽  
Vol 7 (0) ◽  
pp. 27-35
Author(s):  
Shin-ichi IZUMI
Keyword(s):  
Mean Convergence ◽  
The Mean
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