On A Class of New Type Generalized Difference Sequences Related to the P-Normed lp Space Defined By Orlicz Functions
Department of Mathematics, Science and Art Faculty in Adiyaman, Adiyaman University, Adiyaman, TurkeyAbstract
The idea of difference sequence spaces were defined by Kizmaz [6] and generalized by Et and Colak [5]. Later Esi et al. [4] introduced the notion of the new difference operator for fixed n,m∈N. In this article we introduce new type generalized difference sequence space
using by the Orlicz function. We give various properties and inclusion relations on this new type difference sequence space.
Keywords: Orlicz function, difference sequence space, solid space, symmetric space
American Journal of Applied Mathematics and Statistics, 2013 1 (4),
pp 52-56.
DOI: 10.12691/ajams-1-4-1
Received May 06, 2013; Revised June 19, 2013; Accepted June 20, 2013
Copyright © 2013 Science and Education Publishing. All Rights Reserved.Cite this article:
- ESİ, AYHAN. "On A Class of New Type Generalized Difference Sequences Related to the P-Normed lp Space Defined By Orlicz Functions." American Journal of Applied Mathematics and Statistics 1.4 (2013): 52-56.
- ESİ, A. (2013). On A Class of New Type Generalized Difference Sequences Related to the P-Normed lp Space Defined By Orlicz Functions. American Journal of Applied Mathematics and Statistics, 1(4), 52-56.
- ESİ, AYHAN. "On A Class of New Type Generalized Difference Sequences Related to the P-Normed lp Space Defined By Orlicz Functions." American Journal of Applied Mathematics and Statistics 1, no. 4 (2013): 52-56.
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1. Introduction
Throughout the article w, and
denote the spaces all, bounded and p absolutely summable sequences, respectively. The zero sequence is denoted by
. The sequence space
was introduced by Sargent [11], who studied some of its properties and obtained its relationship with the space
. Later on it was investigated from sequence space point of view by Rath [9], Rath and Tripathy [10], Tripathy and Sen [15], Tripathy and Mahanta [14], Esi [2] and others.
An Orlicz function is a function M: [0,∞)→ [0,∞) , which is continuous, non-decreasing and convex with M(0)=0, M(x) > 0 for x > 0 and M(x).
An Orlicz function is said to satisfy Δ2-condition for all values of u, if there exists a constant K > 0, such that M(2u) KM(u), u
0.
Remark. An Orlicz function satisfies the inequality for all
.
Lindenstrauss and Tzafriri [7] used the idea of Orlicz function to construct the sequence space
![]() |
The space with the norm
![]() |
becomes a Banach space which is called an Orlicz sequence space. The space is closely related to the space
which is an Orlicz sequence space with
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In the later stage different Orlicz sequence spaces were introduced and studied by Tripathy and Mahanta [14] , Esi [1], Esi and Et [3], Parashar and Choudhary [8], and many others.
Kizmaz [6] defined the difference sequence spaces (Δ), c(Δ) and co(Δ) as follows:
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for Z = , c and co, where Δx =
=
for all k ∈ N.
The above spaces are Banach spaces, normed by
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Later, the difference sequence spaces were generalized by Et and Çolak [5] as follows: Let be fixed integer, then
for
, where
and so
.
They showed that the above spaces are Banach spaces, normed by
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After then, the notion new type of difference sequence spaces were further generalized Esi and et.al. [4] as follows:
Let be fixed integers, then
![]() |
for , where
and
for all
. The new type generalized difference has the following binomial representation:
![]() |
They showed that the above spaces are Banach spaces, normed by
![]() |
where, for
;
and
2. Definitions and Background
Throughout the article denotes the set of all subsets of N, the set of natural numbers, those do not contain more than s elements. Further
will denote a non-decreasing sequence of positive real numbers such that
for all n∈N. The class of all the sequences
satisfying this property is denoted by Φ.
The space introduced and studied by Sargent [11] is defined as follows:
![]() |
Recently Tripathy and Mahanta [13] defined and studied the following sequence space: Let M be an Orlicz function, then
![]() |
The purpose of this paper is to introduce and study a class of new type generalized difference sequences related to the space using by Orlicz function.
In this article we introduce the following sequence space: Let M be an Orlicz function and p= be bounded sequence of strictly positive real numbers and
be fixed integers, then
![]() |
Taking for all k and m=n=1 i.e., considering only first difference we have the following difference sequence space which were defined and studied by Tripathy and Mahanta [13]
![]() |
Taking for all k, M(x)=x and m=n=1 i.e., considering only first difference we have the following difference sequence space which were defined and studied by Tripathy [12]
![]() |
Taking for all k, M(x)=x and n=1, we have the following difference sequence space which were defined and studied by Esi [2]
![]() |
The space for
is defined by Rath [9] as follows:
![]() |
Let be a sequence, then S ( X ) denotes the set of all permutations of the elements of
i.e. , S ( X ) = {
: π ( k ) is a permutation on N}. A sequence space E is said to be symmetric if S ( X ) ⊂ E for all x ∈ E.
A sequence space E is said to be solid (or normal ) if E , whenever (xk) ∈ E and for all sequences of scalars (αk) with
for all k ∈ N
A sequence space E is said to be monotone, if it contains the canonical pre-images of its step spaces.
The following inequality will be used throughout the paper
![]() |
where and
are complex numbers,
and
3. Main Results
In this section we prove some results involving the sequence space
Theorem 1. Let p= be bounded sequence of strictly positive real numbers.Then the space
is a linear space over the complex field C.
Proof: Let ,
and
C. Then there exists positive numbers
and
such that
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and
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Let . Since M is non-decreasing and convex
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Hence
Theorem 2. Let p= be bounded sequence of strictly positive real numbers and
. Then
is a linear topological space paranormed by
![]() |
where for
;
for m=0 and r=m for n=0.
Proof: Clearly . Next
=
implies
and such as
, therefore
=0. It can be easily shown that
=0
=
Next, let and
be such that
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and
![]() |
Let . Then we have
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Since the are non-negative, we have
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Next, for , without loss of generality, let
, then
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where
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So, the continuity of the scalar multiplication follows from the above inequality.
Theorem 3. if and only if
Proof: Let and
Then
![]() |
for some .
So,
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Therefore
Conversely , let . Suppose that
.Then there exists a sequence of natural numbers
such that
. Let
. Then there exists
such that
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Now we have
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Therefore . As such we arrive at a contradiction. Hence
The following result is a consequence of Theorem 3.
Corollary 4: Let M be an Orlicz function. Then if and only if
and
for all s=1,2,3,... .
Theorem 5: Let p= be bounded sequence of strictly positive real numbers and let
be Orlicz functions satisfying Δ2-condition. Then
![]() |
Proof: Let . Then we have
![]() |
for some
Let and choose
with
such that
for
. Let
for all m and n and for any
, let
![]() |
where the first summation is over and the second is over
. For the first summation above, we can write
![]() | (1) |
For the second summation, we will make following procedure. For , we have
![]() |
Since M is non-decreasing and convex, it follows that
![]() |
Since M satisfies Δ2 condition, we can write
![]() |
Hence
![]() | (2) |
By (1) and (2), we have
Taking in Theorem 5, we have the following result.
Corollary 6: Let p= be bounded sequence of strictly positive real numbers and let M be an Orlicz function satisfying Δ2-condition. Then
![]() |
From Theorem 3 and Corollary 6, we have
Corollary 7: Let p= be bounded sequence of strictly positive real numbers and let M be an Orlicz function satisfying Δ2-condition. Then
![]() |
if and only if
Corollary 8: The space is not solid and symmetric in general.
Proof: To show this space is not solid and symmetric in general, consider the following examples, respectively.
Example 1. Let m=n=1, and
for all k
. Consider
for all k
and M(x)=x. Then
but
. Hence the space is not solid in general.
Example 2. Let m=n=1, and
for all k
and M(x)=x. Then the sequence
define
for all k
is in
. Consider the sequence
, the rearrangement of
define as follows
![]() |
Then . Hence the space is not symmetric in general.
Finally, in this section, we consider that and
are any bounded sequences of strictly positive real numbers. We are able to prove below results only under additional conditions.
Corollary 9: a) If for all k, then
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b) If for all k, then
![]() |
c) Let for all k and
be bounded, then
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Proof: Using the same technique as in Theorem 4 in [1], it is easy to prove the Corollary 9.
Acknowledgement.
The author would like to thank the anonymous reviewer for his/her careaful reading and making some useful comments on earlier version of this paper which improved the presentation and its readability.
References
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[13] | Tripathy, B.C. and Mahanta, S., On a class of difference sequences related to the lp space defined by Orlicz functions, Soochow J. Math. 29 (2003), no. 4, 379-391 | ||
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