scholarly journals On some spaces of summable sequences and their duals

Author(s):  
Geraldo Soares de Souza ◽  
G. O. Golightly

Suppose thatSis the space of all summable sequencesαwith‖α‖S=supn≥0|∑j=n∞αj|andJthe space of all sequencesβof bounded variation with‖β‖J=|β0|+∑j=1∞|βj−βj−1|. Then forαinSandβinJ |∑j=0∞αjβj|≤‖α‖S‖β‖J; this inequality leads to the description of the dual space ofSasJ. It, related inequalities, and their consequences are the content of this paper. In particular, the inequality cited above leads directly to the Stolz form of Abel's theorem and provides a very simple argument. Also, some other sequence spaces are discussed.

Mathematics ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 268 ◽  
Author(s):  
Kuddusi Kayaduman ◽  
Fevzi Yaşar

In 1978, the domain of the Nörlund matrix on the classical sequence spaces lp and l∞ was introduced by Wang, where 1 ≤ p < ∞. Tuğ and Başar studied the matrix domain of Nörlund mean on the sequence spaces f0 and f in 2016. Additionally, Tuğ defined and investigated a new sequence space as the domain of the Nörlund matrix on the space of bounded variation sequences in 2017. In this article, we defined new space and and examined the domain of the Nörlund mean on the bs and cs, which are bounded and convergent series, respectively. We also examined their inclusion relations. We defined the norms over them and investigated whether these new spaces provide conditions of Banach space. Finally, we determined their α­, β­, γ­duals, and characterized their matrix transformations on this space and into this space.


2007 ◽  
Vol 57 (4) ◽  
Author(s):  
Ekrem Savas ◽  
Vatan Karakaya

AbstractIt is natural to expect that lacunary almost convergence must be related to the some concept of lacunary almost bounded variations in the some view as almost convergence is related to almost bounded variation. The purpose of this paper is to examine this new concept in some details. Some inclusion theorems have been established.


1970 ◽  
Vol 22 (4) ◽  
pp. 863-874 ◽  
Author(s):  
William H. Ruckle

Our aim in this paper, generally stated, is to formulate an abstract concept of the notion of the sum of a numerical series. More particularly, it is a study of the type of sequence space called “sum space”. The idea of sum space arose in connection with two distinct problems.1.1 The Köthe-Toeplitz dual of a sequence space T consists of all sequences t such that st ∈ l1 (absolutely summable sequences) for each s∈T. It is known that if cs or bs is used in place of l1, an analogous theory of duality for sequence spaces can be developed (cf. [2]). What other spaces of sequences can play a rôle analogous to l1? This problem is treated in [6].1.2. Let {xn, fn} be a complete biorthogonal sequence in (X, X*), where X is a locally convex linear topological space and X* is its topological dual space.


2002 ◽  
Vol 30 (7) ◽  
pp. 383-392 ◽  
Author(s):  
Suthep Suantai ◽  
Winate Sanhan

Theβ-dual of a vector-valued sequence space is defined and studied. We show that if anX-valued sequence spaceEis a BK-space having AK property, then the dual space ofEand itsβ-dual are isometrically isomorphic. We also give characterizations ofβ-dual of vector-valued sequence spaces of Maddoxℓ(X,p),ℓ∞(X,p),c0(X,p), andc(X,p).


Author(s):  
B. E. Rhoades

AbstractIn a series of papers, the author has previously investigated the spectra and fine spectra for weighted mean matrices, considered as bounded operators over various sequence spaces. This paper examines the spectra of weighted mean matrices as operators over bνv0, the space of null sequences of bounded variation.


2019 ◽  
Author(s):  
Vakeel Ahmad Khan ◽  
Hira Fatima ◽  
Mobeen Ahmad

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.


Filomat ◽  
2019 ◽  
Vol 33 (2) ◽  
pp. 483-492
Author(s):  
Ekrem Savaş

In this paper, by using Orlicz function and almost lacunary bounded variation we introduce and examine a new sequence space in 2-normed spaces. We also study some basic topological and algebraic properties of these spaces. In addition, we shall established inclusion theorems between these sequence spaces.


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