The Essential Norm of Multiplication Operators on Lorentz Sequence Spaces

2016 ◽  
Vol 41 (1) ◽  
pp. 245 ◽  
Author(s):  
René E. Castillo ◽  
Julio C. Ramos-Fernández ◽  
Margot Salas-Brown
2020 ◽  
Vol 39 (6) ◽  
pp. 1407-1414
Author(s):  
Julio C. Ramos-Fernández ◽  
Margot Salas-Brown

We calculate the measure of non-compactness or the essential norm of the multiplication operator Mu acting on Orlicz sequence spaces lφ. As a consequence of our result, we obtain a known criteria for the compactness of multiplication operator acting on lφ.


2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Sei-Ichiro Ueki ◽  
Luo Luo

We estimate the essential norm of a compact weighted composition operator acting between different Hardy spaces of the unit ball in . Also we will discuss a compact multiplication operator between Hardy spaces.


2016 ◽  
Vol 49 (4) ◽  
Author(s):  
B. S. Komal ◽  
Suruchi Pandoh ◽  
Kuldip Raj

AbstractIn this paper we characterize the compact, invertible and Fredholm multiplication operators on Cesàro sequence spaces.


Author(s):  
KUN TU

Abstract We study super weakly compact operators through a quantitative method. We introduce a semi-norm $\sigma (T)$ of an operator $T:X\to Y$ , where X, Y are Banach spaces, the so-called measure of super weak noncompactness, which measures how far T is from the family of super weakly compact operators. We study the equivalence of the measure $\sigma (T)$ and the super weak essential norm of T. We prove that Y has the super weakly compact approximation property if and and only if these two semi-norms are equivalent. As an application, we construct an example to show that the measures of T and its dual $T^*$ are not always equivalent. In addition we give some sequence spaces as examples of Banach spaces having the super weakly compact approximation property.


2013 ◽  
Vol 7 ◽  
pp. 1461-1469 ◽  
Author(s):  
Pawan Bala ◽  
Anuradha Gupta ◽  
Neha Bhatia

2011 ◽  
Vol 2011 ◽  
pp. 1-36 ◽  
Author(s):  
Robert F. Allen ◽  
Flavia Colonna ◽  
Glenn R. Easley

Let be the space of complex-valued functions on the set of vertices of an infinite tree rooted at such that the difference of the values of at neighboring vertices remains bounded throughout the tree, and let be the set of functions such that , where is the distance between and and is the neighbor of closest to . In this paper, we characterize the bounded and the compact multiplication operators between and and provide operator norm and essential norm estimates. Furthermore, we characterize the bounded and compact multiplication operators between and the space of bounded functions on and determine their operator norm and their essential norm. We establish that there are no isometries among the multiplication operators between these spaces.


2021 ◽  
Author(s):  
René E. Castillo ◽  
Yesid A. Lemus-Abril ◽  
Julio C. Ramos-Fernández

2016 ◽  
Vol 57 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Kuldip Raj ◽  
Charu Sharma ◽  
Suruchi Pandoh

AbstractIn this paper, we characterize the compact, invertible, Fredholm and closed range multiplication operators on Cesàro-Orlicz sequence spaces.


2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Julio C. Ramos-Fernández ◽  
María A. Rivera-Sarmiento ◽  
Margot Salas-Brown

In this article, we establish an important property about the growth of sequences in the dual space of Cesàro sequence spaces. As a consequence of this fact, we calculate the measure of noncompactness or the essential norm of the multiplication operator Mu acting on Cesàro sequence spaces cesp.


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