On Interval Valued Generalized Difference Classes Defined by Orlicz Function
1Department of Mathematics, Faculty of Science and Art, Adiyaman University, Adiyaman, Turkey
2Department of Mathematics, Gandhi University, Rono Hills, Arunachal Pradesh, India
Abstract
In this paper, using the difference operator and Orlicz functions, we introduce and examine some generalized difference sequence spaces of interval numbers. We prove completeness properties of these spaces. Further, we investigate some inclusion relations related to these spaces.
Keywords: sequence space, interval numbers, difference sequence, completeness
Turkish Journal of Analysis and Number Theory, 2013 1 (1),
pp 48-53.
DOI: 10.12691/tjant-1-1-10
Received October 01, 2013; Revised November 04, 2013; Accepted November 11, 2013
Copyright © 2013 Science and Education Publishing. All Rights Reserved.Cite this article:
- Esi, Ayhan, and Bipan Hazarika. "On Interval Valued Generalized Difference Classes Defined by Orlicz Function." Turkish Journal of Analysis and Number Theory 1.1 (2013): 48-53.
- Esi, A. , & Hazarika, B. (2013). On Interval Valued Generalized Difference Classes Defined by Orlicz Function. Turkish Journal of Analysis and Number Theory, 1(1), 48-53.
- Esi, Ayhan, and Bipan Hazarika. "On Interval Valued Generalized Difference Classes Defined by Orlicz Function." Turkish Journal of Analysis and Number Theory 1, no. 1 (2013): 48-53.
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1. Introduction
The work of interval arithmetic was originally introduced by Dwyer [3] in 1951. The development of interval arithmetic as a formal system and evidence of its value as a computational device was provided by Moore [15] and Moore and Yang [16]. Furthermore, Moore and others [3]; [4]; [10] and [17] have developed applications to differential equations. Chiao in [2] introduced sequence of interval numbers and defined usual convergence of sequences of interval numbers. Şengönül and Eryilmaz in [20] introduced and studied bounded and convergent sequence spaces of interval numbers. Recently Esi studied strongly λ-and strongly almost λ-convergent sequences spaces of the interval numbers in [5], respectively. Also, Esi studied some new type sequence space of the interval numbers in [6, 7] and lacunary sequence spaces for interval numbers in [8]. In Hazarika [11] introduced the notion of λ-ideal convergent interval valued di¤erence classes defined by Musielak-Orlicz function.
Kizmaz [12] introduced the notion of di¤erence sequence spaces as follows:
![]() |
for
and
Later on, the notion was generalized by Et and Çolak [9] as follows:
![]() |
for
and
where
and also this generalized difference notion has the following binomial representation:
![]() |
Recall in [18], [13] that an Orlicz function M is continuous, convex, non-decreasing function define for such that
and
for
and
as
If convexity of Orlicz function is replaced by
then this function is called the modulus function and characterized by Ruckle [19]. An Orlicz function
is said to satisfy
for all values
,if there exists
such that
Subsequently, the notion of Orlicz function was used to defined sequence spaces by Altin et. al., [1], Tripathy and Mahanta [21], Tripathy et. al., [22], Tripathy and Sarma [23] and many others.
2. Preliminaries
A set consisting of a closed interval of real numbers such that
is called an interval number. A real interval can also be considered as a set. Thus we can investigate some properties of interval numbers, for instance arithmetic properties or analysis properties. We denote the set of all real valued closed intervals by
Any elements of
is called closed interval and denoted by
That is
An interval number
is a closed subset of real numbers (see [2]). Let
and
be first and last points of the interval number
respectively. For
we have
![]() |
![]() |
and if , then
![]() |
and if , then
![]() |
![]() |
The set of all interval numbers is a complete metric space under the mertic
defined by
![]() |
[15].
In the special case and
we obtain usual metric of
Let us define transformation by
Then
is called sequence of interval numbers and
is called
term of the interval numbers sequence
The set of all sequences of the interval numbers denoted by
cf. [2].
A sequence of interval numbers is said to be convergent to the interval number
if for each
there exists a positive integer
such that
for all
and we denote it by
Thus, and
[2].
A sequence space is said to be solid (or normal) if
whenever
for all sequences
of scalars with
for all
A sequence space is said to be symmetric if
implies
where
is a permutation of
A sequence space is said to be monotone if
contains the canonical pre-images of all its step spaces.
Let and
be a sequence space. A K-step set of
is a class of sequences
A canonical pre-image of a sequence
is a sequence
defined as follows:
![]() |
A canonical pre-image of a step set is a set of canonical pre-images of all elements in
, i.e.
is in canonical pre-image
if and only
is canonical pre-image of some
A sequence space is said to be sequence algebra if
whenever
A sequence space is said to be convergence free if
whenever
and
whenever
, where
is the zero element.
Remark 2.1. A sequence space is solid implies
is monotone.
3. Main Results
In this paper we introduce and examine some generalized difference sequences of interval numbers using the Orlicz functions.
Definition 3.1. Let be a sequence of interval numbers and
be an Orlicz function. We define the following sequence spaces:
![]() |
![]() |
![]() |
where
![]() |
Throughout the paper, will denote any one of the notation
and
Theorem 3.1. and
are complete metric spaces with the metric
![]() |
Proof. Let be any Cauchy sequence in
where
for each
Then for given
For a fixed
and choose
such that
Then there exists
such that
![]() | (3.1) |
Hence
![]() |
Then is a Cauchy sequence in
and so
is a convergent sequence in
Let
Again from (3.1)
![]() |
Hence is a Cauchy sequence in
for all
and so
is a convergent sequence in
for all
Let
for all
For we have
![]() |
Similarly we have
![]() |
Thus exists. Let
Proceeding in this way inductively we conclude that
for all
Using continuity of
, we have
![]() |
Thus for all we obtain that
![]() |
That is
![]() |
Then the inequality
![]() |
implies that This completes the proof.
Theorem 3.2. The classes of interval numbers of sequences and
are nowhere dense subsets of
Proof. From Theorem 3.1. we have and
are closed subsets of the complete metric space
Also
and
are proper subsets which follows from the following example.
Example 3.1. Let and
Consider the interval sequence
defined as follows:
![]() |
and
![]() |
Thus but
Hence the result.
Theorem 3.3. for
and the inclusions are strict.
Proof. We give the proof for the inequality only. The rest of the results follows similar way. Let
Then for some
we have
![]() | (3.2) |
Since
![]() |
Then from the equation (3.2) and the continuity of , the result follows from the following relation
![]() |
This shows that
To show that the inclusions are strict, consider the following examples.
Example 3.2. Let and
Consider the sequence of interval numbers
defined by
![]() |
i.e. as
and
as
Thus
but
Hence the inclusion is strict.
Example 3.3. Let and
Consider the sequence of interval numbers
defined by
![]() |
Then Thus
Hence the inclusion is strict.
Theorem 3.4. Let and
be two Orlicz functions. Then
(i)
(ii)
Proof. (i) We prove the result for and the rest of the cases will follow similarly. Let
Then for
we have
![]() | (3.3) |
Let and
with
such that
for
. We write
![]() |
Then for
![]() |
we have
![]() |
where and
denotes the integer part of
Given
by the definition of Orlicz function
for
we have
![]() |
for and
using (3.3).
Again for
![]() |
we have
![]() |
for and
using (3.3).
Thus for we have
![]() |
Hence Thus
![]() |
(ii) It will follows from the following inequality
![]() |
The proof of the following result is also routine work.
Theorem 3.5. Let and
be two Orlicz functions satisfying
If
then
where
Theorem 3.6. The classes of sequences of interval numbers and
are not sequence algebra in general.
Proof. The result follows from the following example.
Example 3.4. Let and
Consider the two sequences of interval numbers
defined by
![]() |
Therefore for all we have
![]() |
Thus Now, we have
![]() |
i.e. This completes the proof.
Theorem 3.7. The classes of interval numbers of sequences and
are not convergence free.
Proof. Let and
Consider the interval sequence
defined as follows:
![]() |
and
![]() |
Hence as
Thus
Let
defined as follows:
![]() |
and
![]() |
Thus Therefore the classes of interval numbers
and
are not convergence free.
Theorem 3.8. The classes of interval numbers and
are neither monotone nor solid.
Proof. Let and
Consider the interval sequence
defined by:
![]() |
and
![]() |
i.e. as
Thus
Let be a subset of
and let
be the canonical pre-image of the J-step set
of
defined as follows:
is the canonical pre-image of
implies
![]() |
Now
![]() |
and
![]() |
Thus Therefore the classes of interval numbers
and
are not monotone. By the Remark 2.1, these spaces are not solid.
Now let’s define the sequence by
![]() |
and , thus
Let be a subset of
and let
be the canonical pre-image of the J-step set
of
defined as follows:
is the canonical pre-image of
implies
![]() |
Now
![]() |
and
![]() |
Therefore and
is not monotone. By the Remark 2.1, this space is not solid.
Theorem 3.9. The classes of interval numbers and
are not symmetric.
Proof. The result follows from the following example.
Example 3.5. Let and
Consider the interval sequence
defined by
![]() |
and
Thus Let the sequence of interval numbers
be a rearrangement of the sequence of interval numbers
defined as follows:
![]() |
i.e.
![]() |
Then for all odd and
satisfying
we have
![]() |
From the last two equation, it is clear that is unbounded, thus
Therefore the class
is not symmetric.
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