Some Fixed Point Theorems for Multivalued Mappings in Banach Algebras and Application to Integral Inclusions
Higher School of Sciences and Technologies of Hammam Sousse, Street Lamin El Abbassi 4011, Hammam Sousse, TunisiaAbstract | |
1. | Introduction |
2. | Preliminaries |
3. | Fixed Point Theory in Banach Algebras |
4. | Another Direction |
5. | Functional Integral Inclusion |
References |
Abstract
In this paper, we present new multivalued analogues of the krasnoselskii fixed point theorems, for the sum AB+C, where the operators A;B and C are D-set Lipcshitzian with respect to a measure of non-compactness which satisfies condition (m). Our results generalize, prove and extend well-known results in the literature. An application to solving non linear integral inclusion is given.
Keywords: measure of noncompatness, Banach algebras, condensing multimap, integral equations
Received December 20, 2016; Revised February 27, 2017; Accepted March 20, 2017
Copyright © 2017 Science and Education Publishing. All Rights Reserved.Cite this article:
- Mohamed Boumaiza. Some Fixed Point Theorems for Multivalued Mappings in Banach Algebras and Application to Integral Inclusions. Turkish Journal of Analysis and Number Theory. Vol. 5, No. 2, 2017, pp 69-79. https://pubs.sciepub.com/tjant/5/2/5
- Boumaiza, Mohamed. "Some Fixed Point Theorems for Multivalued Mappings in Banach Algebras and Application to Integral Inclusions." Turkish Journal of Analysis and Number Theory 5.2 (2017): 69-79.
- Boumaiza, M. (2017). Some Fixed Point Theorems for Multivalued Mappings in Banach Algebras and Application to Integral Inclusions. Turkish Journal of Analysis and Number Theory, 5(2), 69-79.
- Boumaiza, Mohamed. "Some Fixed Point Theorems for Multivalued Mappings in Banach Algebras and Application to Integral Inclusions." Turkish Journal of Analysis and Number Theory 5, no. 2 (2017): 69-79.
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1. Introduction
The study of the linear integral equation in Banach algebra was initiated by Dhage via fixed point theorems [14, 16, 17]. Recently, many authors are interested in the study of non linear integral equations and integral inclusions, in Banach algebras, by using the argument of measure of noncompactness [1, 2, 5, 6, 7, 13, 15, 18, 19]. Given a Banach algebra X and a closed bounded interval J = [0, a] in IR, we consider the following functional integral inclusion
![]() | (1) |
where
and
The functional integral inclusion (1) can be transformed to the following fixed point problem
![]() |
where A, B and C are multivalued operators acting on the Banach algebra C(J, X). Note that a particular case of (1) has been studied by B.C Dhage [11] where X is the Banach algebra IR.
In order to study problem (1), we look at the nonlinear equation
![]() |
where S is a non empty closed convex subset (not necessarily bounded) of a Banach algebra X and A, B, C are upper semi-continuous or closed multivalued mappings acting on X.
In [11], by using a propriety of the Hausdorff measure of noncompatness, Dhage has examined the nonlinear equation where A and B are multivalued operators acting on a Banach algebra. In [8], authors introduced a new class of multivalued mappings of the form
where A and C are multivalued operators acting a on Banach algebra. Using this concept, they presented some fixed point theorems for the operator AB + C in weak topology setting.
The present paper is organized as follows. In section 2, we give some useful preliminaries and definitions which will be needed in the sequel. In section 3, by using the propriety (m) of a measure of non compactness on X, we present some hybrid fixed point theorems for the operator AB + C. For this, we use the propriety of D-set lipschitzian with respect to
for the multivalued operators A, B and C. On another direction, in section 4, we use the class of multivalued operator
to prove some fixed point theorems for the sum AB +C. This is based on the propriety of
-condensing of the operato
for any measure of non compactness
on X. Our results generalize, prove and extend well known results, for single valued mappings [13, 14, 15, 16, 19] and for multivalued mappings [11].
Section 5 is devoted to establishing an existence theorem for the nonlinear integral inclusions (1), where X is a separable Banach algebra, as a consequence of our Theorem 3.2.
2. Preliminaries
Throughout this paper, Let X be a Banach space endowed with the norm For convenience let
![]() |
We denote by B(x, r) the closed ball centered at x with radius r. For a subset S of X, we write , convS, and
to denote the closure, the convex hull and the closed convex hull of the subset S, respectively. We write
to denote the convergence with respect to the norm of X.
Let X and Y be two Banach spaces. A correspondence is called a multivalued operator or a multivalued mapping on X into Y. For any subset A of X, define
![]() |
The range of T is the image T(X) of X. We can identify T with its graph GrT the subset of X × Y given by
![]() |
A point is called a fixed point of T if
Definition 2.1 Let be a multivalued mapping.
- We say that T is upper semi-continuous if is an open set in X, for all open subset U of Y.
- We say that T is closed if its graph is closed in In other words, if
be a sequence in GrphT such that
then we have that
- We say that un element x in X is a fixed point of T if
- We say that T is compact if its range T(X) is relatively compact in Y.
- We say that T is completely continuous if it is upper semi-continuous and, for all bounded subset of X,
is relatively compact.
In the following proposition we recall some essential properties of upper semi-continuous and closed multivalued mappings in Banach spaces.
Proposition 2.1 [26]. Let X and Y be Banach spaces, and let be a multivalued mapping.
1) If T is upper semi-continuous and compact-valued, then for each compact subset K of X, T(K) is compact.
2) If T is upper semi-continuous and compact-valued, then T is closed.
3) If Y is compact, then T is closed if and only if it is upper semi-continuous and closed-valued.
4) If T is compact-valued, then T is upper semi-continuous if and only if for all sequence in GrphT such that
the sequence
has a limit point in T(x).
We recall the KaKutani-Fan fixed point principle for upper semi-continuous multivalued mappings.
Theorem 2.1 [20]. Let K be a compact convex subset of a Banach space E and let be an upper semi-continuous multivalued mapping. Then T has a fixed point.
We cite the following generalizations of the KaKutani-Fan fixed point principle.
Theorem 2.2 (Bohmenblust-Karlin, see [21])) Let S be a closed, bounded and convex subset of a Banach space E and let be an upper semi-continuous multivalued mapping with compact range. Then T has a fixed point.
Theorem 2.3 (O'Regan [24]). Let S be a closed, bounded and convex subset of a Banach space E and let be closed compact multivalued mapping. Then T has a fixed point.
The compactness of the operator T is weakened to condensing operator by using the notion of measure of noncompactness in Banach spaces.
Definition 2.2 A function is said to be a measure of noncompactness on X (MNC, for short), if it satisfies the following properties:
1. for all bounded subsets
2. Monotonicity: For any bounded subsets
of X we have
![]() |
3. Nonsingularity: for all
bounded set of
4. if and only if
is relatively compact in X.
5. If is a decreasing sequence of sets in
satisfying
then the limiting set
is non empty.
The MNC is said to be positive homogeneous provided
![]() |
The MNC is said to be subadditive if
![]() |
The above notion is a generalization of the Hausdorff measure of noncompactness defined on each bounded set
of X by
![]() |
It is well known that is homogenous, subadditive and satisfies the set additivity property. The details of measure of noncompactness appear in Deimling [10] and Zeidler [25].
Definition 2.3 Let be a MNC on X, we say that the multivalued mapping
is
-condensing, if for any
is bounded and
for
.
We say that the multivalued mapping is a
-set-Lipschitzian (with respect to
) if there exists a continuous nondecreasing function
with
such that
![]() |
for all bounded subset with
If
we say that T is a k-set-Lipschitzian and if k < 1, then T is called a k-set-contraction. If
for r > 0, then T is called a nonlinear
-set-contraction.
For any let
![]() |
For and
let
![]() |
The function defined by
![]() |
is a metric on and is called the Hausdorff metric on X (see [26]). It is clear that
for any
Proposition 2.2 [26] If then
is equivalent to the following assertion:
and
Definition 2.4 A multivalued mapping is called
-Lipschitzian if there exists a continuous nondecreasing function
with
such that
![]() |
for all The function
is called a
-function of T on X. If
for r > 0, then T is called a Lipschitzian multivalued mapping. In particular, if K < 1, then T is called a multivalued contraction. If
satisfies
then T is called a nonlinear contraction multivalued mapping with contraction function
3. Fixed Point Theory in Banach Algebras
Definition 3.1 An algebra X is a vector space endowed with an inner operation noted by (.) which is associative and bilinear.
A normed algebra is an algebra endowed with a norm such that
![]() |
A complete normed algebra is called a Banach algebra.
Definition 3.2 [5]. We state that a measure of noncompactness on a Banach algebra X satisfies the condition (m) if for arbitrary bounded sets
of X, the following inequality is satisfied
![]() |
Lemma 3.1 [3]. For any bounded subsets and
of X, we have
![]() |
According to Lemma 3.1, the Hausdorff measure of noncompactness satisfies condition (m).
We note that condition (m) was used for the first time in [3] for measures of noncompactness defined on the Banach algebra C[a, b].
Example 3.1 Let X = BC(IR+) the Banach space of continuous and bounded functions on IR+ equipped with the standard norm Obviously BC(IR+) has also the structure of Banach algebra with the standard multiplication of functions. For all
L > 0 and
we pose
![]() |
According to [4], is a measure of noncompactness on BC(IR+)which satisfies condition (m) on the family of nonnegative functions in BC(IR+) (see [1]).
We begin this section by proving the following fixed point theorem which extends Theorem 2.2 in [12].
Theorem 3.1 Let X be a Banach space, a MNC on X and S a closed convex subset of X. Let
be a closed an
-condensing mapping such that T(S) is bounded. Then T has a fixed point.
Proof. Let x0 be an arbitrary element in S. We pose
![]() |
The set since
Let
We Show that
. Clearly L is a closed convex subset of S and
Thus,
This implies
Hence,
![]() |
Consequently, Hence,
As a result
![]() |
Suppose that we have
![]() |
Then and consequently L is compact and convex. By Theorem 2.3, the multivalued mapping
has a fixed point.
Theorem 3.2 Let S be a closed convex subset of a Banach algebra X and a subadditive MNC on X satisfying condition (m). Let
and
be multivalued mappings such that:
1. A, B are upper semi-continuous and C is closed,
2. A, B and C are D-set Lipschitzian (with respect to ) with D-function
,
and
respectively,
3. for all is a convex subset of S,
4. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
Proof. Let
![]() |
Since A, B have compact values and C has closed values, assumption 3) guarantees that T is well defined. We show that T has closed graph. Let
and
![]() |
Let such that
and
Since A and B are upper semicontinous, by Proposition 2.1 we can suppose that
It yields that
Since C has closed graph, we get
then
Hence AB + C has closed graph. Let
be a bounded subset of S such that
It is clear that
is bounded and we have
![]() |
Thus, the multivalued mapping AB + C is -condensing. From Theorem 3.1, AB + C has a fixed point.
If we suppose that the multivalued mapping B is completely continuous, we obtain the following result.
Theorem 3.3 Let S be a closed convex subset of a Banach algebra X and a subadditive MNC on X satisfying condition (m). Let
and
be multivalued mappings such that:
1. A is upper semi-continuous and C is closed,
2. A and C are D-set Lipschitzian (with respect to ) with D-functions
and
, respectively,
3. B is completely continuous,
4. for all is a convex subset of S,
5. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
Proof. As in the proof of Theorem 3.2, the operator
![]() |
is well defined and has a closed graph. Let be a bounded subset of S such that
Since B is completely continuous
and we have
![]() |
Then T is -condensing and the proof is concluded by Theorem 3.1.
In the following result, we interested in the case where A, B and C are D-Lipschitzian. We need the following lemmas which are essential for the proof.
Lemma 3.2 Let X be a Banach space, S be a non-empty subset of X and be a
-Lipschitzian multivalued mapping with
-function
Then for any bounded subset
of S,
is bounded.
Proof. Let be a bounded subset of S. Then there is constant r > 0 such that
for all
Fix Since T is
-Lipschitzian, for all
we have
![]() |
Hence is bounded.
Lemma 3.3 Let X be a Banach space and let be a D-Lipschitzian multivalued mapping with D-function
. Then T is upper semi-continuous.
Proof. Let be a sequence in X converging to a point
and let
such that
for all integer n. We have
![]() |
Then Let
there exists an integer N such that, for all
This implies that
![]() |
and consequently is relatively compact. Then there exists a subsequence
which converges to
According to Proposition 2.1, T is upper semi-continuous.
Lemma 3.4 Let X be a Banach space and be a
-Lipschitzian multivalued mapping with a
-function Then T is
-set-Lipschitzian with respect to the Hausdorff measure of noncompactness.
Proof. Let be a bounded subset of X. From Lemma 3.2,
is bounded. Let r > 0 such that
there exits a finite subset
of
such that Let
there exists
such that
Since T is D-Lipschitzian, we have
![]() |
According to Proposition 2.2, Consequently
![]() |
On the other hand, from Lemma 3.3 T is upper semi-continous and, by Proposition 2.1, is compact. For each
there exists
in
such that
![]() |
Consequently,
![]() |
That is for each
Letting
and by the continuity of
, we deduce that
Hence T is D-set Lipchitzian with D-function
Now we are ready to prove the following result.
Theorem 3.4 Let S be a closed convex subset of a Banach algebra X. Let be multivalued mappings such that:
1. A, B and C are D-Lipschitzian with D-functions
and
respectively,
2. for all
is a convex subset of S,
3. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
Proof. From Lemma 3.3, the mappings A, B and C are upper semi-continuous, in particular, by Proposition 2.1, the operator C is closed. Further, by Lemma 3.4, the mappings A, B and C are D-set Lipschitzian with respect to . Since the measure
satisfies condition (m), all assumptions of Theorem 3.2 are satisfies and the proof is concluded.
The following result is a direct consequence of Theorem 3.3 and Lemma 3.4.
Theorem 3.5 Let S be a closed convex subset of a Banach algebra X. Let and
three multivalued mappings such that:
1. A and C are D-Lipschitzian with D-functions and
, respectively,
2. B is completely continuous,
3. for all
is a convex subset of S,
4. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
In the particular case where A and C are Lipschitzian, we obtain the following corollary which extends Theorem 3.5 in [11].
Corollary 3.1 Let S be a closed convex subset of a Banach algebra X. Let be multivalued mappings and let
such that:
1. A and C are Lipschitzian with Lipschitz constant and
, respectively,
2. B is completely continuous,
3. for all is a convex subset of S,
4. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
In the particular case where A, B and C are single valued mappings, we obtain the following result which generalizes Theorem 1.4 in [19].
Corollary 3.2 Let S be a closed convex subset of a Banach algebra X and let such that:
1. A and C are D-Lipschitzian with D-functions and
respectively,
2. B is completely continuous,
3. for all is a an element of S,
4. A(S), B(S) and C(S) are bounded.
Then the equation has at least one solution provided
![]() |
4. Another Direction
In the following, we introduce the operator for multivalued mappings and we well use it to prove existence theorems of the equation
.
Definition 4.1 [8] Let X be a Banach algebra and be multivalued mappings. We say that the mapping
is well defined on
and we write
![]() |
Theorem 4.1 Let X be a Banach algebra, a MNC on X and
a subadditive MNC on X which satisfies condition (m). Let S be a non-empty closed convex subset of X and let
be three multivalued mappings satisfying the following properties:
1. A, B are upper semi-continuous and C is closed,
2. A and C are -set-Lipschitzian (with respect to
) with
-functions
and
, respectively,
3. A(X), C(X) and B(S) are bounded,
4. for all y
is convex and
5. is
-condensing.
Then the equation has at least one solution in S if
![]() |
Proof. Fix and let
Consider
![]() |
Since A(x) is compact and C(x) is closed, it is clear that is well defined. We claim that
has closed graph. Let
be a sequence converging to
and
such that
with
There exist
and
such that
Since A is upper semi-continuous and has compact values, according to Proposition 2.1, there exists a subsequence, we note also
such that
Consequently
Since C has closed graph, we deduce that
which implies that
Hence
has closed graph.
We show that is
-condensing. Fixing a bounded subset
of X such that
It is clear that
is bounded. Since
is subadditive and satisfies condition (m), we have
![]() |
So, is
-condensing. Now all assumptions of Theorem 3.1 are satisfied for the operator
then there exists
such that
Thus
and, so,
Consequently the multivalued mapping
is well defined on B(S). Note that, for all
is equivalent to
By assumption 4), we deduce that
![]() |
is well defined. We show that T has closed graph. Let be a sequence converging to
and
such that
with
We have
then
where
,
and
Since A and B are upper semi-continuous with compact values, by Proposition 2.1, we can suppose that
and
Then
![]() |
and so
![]() |
According to Theorem 3.1, it suffices to verify that T is bounded. In fact
![]() |
then assumption 3) guarantees that T(S) is bounded and the proof is concluded.
As consequence of Theorem 4.1, we derive the following corollary.
Corollary 4.1 Let X be a Banach algebra, S be a nonempty closed convex subset of X and a MNC on X. Let
and
be three multivalued mappings satisfying the following properties:
1. B is upper semi-continuous,
2. A and C are -Lipschitzian with
-functions
and
respectively,
3. A(X), C(X) and B(S) are bounded,
4. for all
is convex and
,
5. is
-condensing.
Then the equation has at least one solution in S if
![]() |
Proof. By Lemma 3.3 and Lemma 3.4, the multivalued mappings A and C are upper semi-continuous and D-set Lipschitzian with respect to . Further, by Proposition 2.1, C has closed graph. All assumption of Theorem 4.1 are satisfied and the proof is concluded.
In the case where B is completely continuous, we can omit assumption 5) in Theorem 4.1 and we get the following result.
Theorem 4.2 Let X be a Banach algebra, S be a non-empty closed convex subset of X and a subadditive MNC on X which satisfies condition (m). Let
and
be three multivalued mappings satisfying the following properties:
1. A is upper semi continuous, B is completely continuous and C have closed graph,
2. A and C are -set-Lipschitzian (with respect to
) with D-functions
and
, respectively,
3. A(X), C(X) and B(S) are bounded,
4. for all
is convex and
. Then the equation
has at least one solution in S if
![]() |
Proof. As in the proof of Theorem 4.1, the operator
![]() |
is well defined and has closed graph. We show that T is -condensing. Let N be a bounded subset of S, it is clear that T(N) is bounded. Further, we have
![]() |
Then
![]() |
Hence T is -condensing.
The following result is a direct consequence of Theorem 4.2, Lemma 3.3 and Lemma 3.4.
Corollary 4.2 Let X be a Banach algebra and S be a non-empty closed convex subset of X. Let and
be three multivalued mappings satisfying the following properties:
1. B is completely continuous,
2. A and C are -Lipschitzian with
-functions
and
, respectively,
3. A(X), C(X) and B(S) are bounded,
4. for all
is convex and
. Then the equation
has at least one solution in S if
![]() |
In the particular case where A, B and C are single valued mappings, we obtain the following result which extends Theorem 1.5 in [19], Theorem 2.1 in [15] and Theorem 2.3 in [16].
Theorem 4.3 Let X be a Banach algebra and S be a non-empty closed convex subset of X. Let and
be three mappings satisfying the following properties:
1. B is completely continuous,
2. A and C are -Lipschitzian with
-functions
and
, respectively,
3. A(X), C(X) and B(S) are bounded with
4.
Then the equation has at least one solution in S if
Proof. From Theorem 4.2 it suffices to verify that is a single-valued mapping from S into itself. Let
be fixed and consider
![]() |
Let we have
![]() |
From a fixed point theorem of Boyd and Wong [9], there is a unique element such that x =AxBy+Cx which is equivalent to
(here
is seen as a multivalued mapping). Moreover, bearing in mind 4) we have that there exists a unique
such that
Hence
is well defined as a single-valued mapping.
Remark 1 Assumption 4) in Theorem 4.3 is satisfied if we suppose that for all
Then, we obtain the following corollary which extends and proves a result due to Dhage cited in [13] (Theorem 2.3) and proved in [14].
Corollary 4.3 Let S be a non-empty closed convex subset of a Banach algebra X and let and
be three mappings satisfying: the following properties:
1. B is completely continuous,
2. A and C are -Lipschitzian with
-functions
and
, respectively,
3. A(X), C(X) and B(S) are bounded,
4. for all
.
Then the equation x = A(x)B(x) + C(x) has at least one solution in S if
![]() |
5. Functional Integral Inclusion
In the following, we suppose that is a separable Banach algebra and
By a solution of (1) we mean a function
that satisfies
![]() |
for some satisfying
and
a.e. for
A multivalued mapping is said to be measurable if for any
the function
is measurable. Further T is said to be integrably bounded if there exists
such that
a.e
for all
For we pose
![]() |
It is known that this set is nonempty if and only if (see [22]). This is the case if T is integrably bounded.
A multifunction is called Carathéodory if
(i) is measurable for each
(ii) is upper semi-continuous a.e. for
A Carathéodory multivalued mapping
is called L1-Carathéodory if for every real number r > 0 there exists a function
such that
![]() |
for all with
Denote
![]() |
To discuss equation (1), we list the following hypotheses.
(H1) The mapping f is bounded and there exists a bounded function such that
![]() |
(H2) The multivalued mapping F is -Carathéodory with growth functions
for all r > 0.
(H3) There exists such that, for all bounded
![]() |
(H4) For all the mapping
is integrably bounded.
(H5) There exists such that
![]() |
(H6) The function is continuous with bounded
Theorem 5.1 Assume that the hypotheses (H1)-(H6) hold. Suppose that there exists r > 0 such that
![]() |
and
![]() |
where Then (1) has a solution in
Proof. For all we pose
![]() |
![]() |
![]() |
We show that operators A, B and C satisfy all assumptions of Theorem 3.2. We pose E = C(J, X) and
![]() |
Step 1. Let and
We have
![]() |
Since x is continuous, then Ax is also continuous. Hence, the operator is well defined as a single valued mapping. For all
we have
![]() |
Then A is Lipschitzian with constant It is clear that
Step 2. We prove that is well defined and D-Lipschitzian. From assumption (H4),
is non empty and, so, Bx is non empty. Let
and
for all
Since
it is clear that
We show that Cx is compact, for all . Let (yn) be a sequence in Cx such that
![]() |
Since and
is compact, then for all
the subset
is relatively compact in X. The pointwise topology coincides with the product topology on
then
![]() |
is relatively compact in with respect to the pointwise topology. Hence, there exists a subsequence, for simplicity we note also
such that
for all
For all
(h the growth function of G(x)). By the convergent dominate theorem, we get
and
![]() |
We deduce that is relatively compact, for all
For all
we have
![]() |
It follows that the family is equicontinuous. By Ascoli theorem's, we deduce that
is relatively compact in
Then, there exists a subsequence
which converge uniformly to
On the other hand, for all
is closed, so
Then,
and
Hence Cx is compact.
We show that C is D-Lipshitzian. Let and
such that
![]() |
Since
![]() |
by Proposition 2,2 there exists such that
for all
and
![]() |
Further the mapping w is measurable (see [18]). We pose we have
![]() |
It follows that By Proposition 2.2, we deduce that
![]() |
Hence the multivalued mapping C is Lipschitzian with constant By Proposition 2.1 and Lemma 3.3, we deduce that C has closed graph. On the other hand, for all
we have
![]() |
For all with
and
we get
![]() |
Step 3. Since the multivalued map F satisfies (H1) and (H2), then the multivalued operator B is upper semiccontinuous with compact values (see [23], Theorem 5.1.2 and corollary 5.1.2). We show that the multivalued mapping B is Lipschitzian, with respect to the Hausdorff measure of nocompactness on C(J, X), also noted . Let
be a subset of S and
where
![]() |
for some For all
we have
![]() |
Then, the subset is equicontinuous in
By the properties of
, we have
![]() |
The multivalued mapping
is integrably bounded with growth function
Further, we have
![]() |
Hence, the multivalued operator B is lipschitzian with respect to .
For all we have
![]() |
Then
Step 4. We show that Ax.Bx + Cx is a convex subset of S, for each . Let
![]() |
and
![]() |
where and
![]() |
Then, for all we have
![]() |
Since and
are convex subsets of X, we get
![]() |
where and
Let with
![]() |
Then
Since
![]() |
By Lemma 3.3 and Lemma 3.4, the multivalued mappings A;B and C satisfy all the conditions of Theorem 3.2 and equation has a solution in C(J, X).
References
[1] | A. Aghajani and M. Aliaskari, “Measure of noncompactness in Banach algebra and application to the solvability of integral equation in BC(IR+)'”, Inf. Sci. Lett 4, No 2, 93-99 (2015). | ||
![]() | |||
[2] | J. Banas and M.A. Taoudi, “Fixed point and solution of operators for the weak topology in Banach algebras”, Taiwainese Journal of Mathematics, 18 (3) (2014), 871-893. | ||
![]() | View Article | ||
[3] | J. Banas M. Lecho, “Fixed point of the product of operators in Banach algebras”, Pan American Math. J., 12 (2002), 101-109. | ||
![]() | |||
[4] | J. Banas, “Measure on noncompactness in the space of continuous tempered functions”, Demonstration Math. 14 (1981), 127-133. | ||
![]() | |||
[5] | J. Banas and L. Olszowy, “On a class of measures of noncompactness in Banach algebras and their application to nonlinear integral equations,” Zeitschrift fur Analysis und ihre Anwendungen, vol. 28, no. 4, pp. 475498, 2009. | ||
![]() | |||
[6] | A. Ben Amar, S. Chouayekh and A. Jerbi, “New fixed point theorems in Banach algebras under weak topology features and application to nonlinear integral equations,” J. Funct. Anal, 259 (9) (2010), 2215-2237. | ||
![]() | View Article | ||
[7] | A. Ben Amar ,S. Chouayekh and A. Jerbi, “Fixed point theory in new class of Banach algebras and application,” Afr. Mat, 24 (2013), 725-724. | ||
![]() | View Article | ||
[8] | A. Ben Amar , M. Boumaiza and D. O'Regan, “Hybrid fixed point theorems for multivalued mappings in Banach algebras under weak topology setting,” J. Fixed Point Theory App, June 2016, Volume 18, Issue 2, pp 327-350. | ||
![]() | View Article | ||
[9] | D W. Boyd and J S W. Wong, “On nonlinear contractions,” Proc. Amer. Math. Soc, 20 (1969), 458-464. | ||
![]() | View Article | ||
[10] | K. Deimling, “Multivalued dfferential equation,” W. de Grayter, 1992. | ||
![]() | |||
[11] | Dhage B C. “Multivalued operators and fixed point theorems in Banach algebras I,” Taiwainaise Journal of Mathematics, 10 (4) (2006), 1025-1045. | ||
![]() | |||
[12] | B C. Dhage, “Some generalization of multivalued version of Shauder's fixed point theorem whith application,” CUBO A Mathematical Journal, 12 (03) (2010), 139-151. | ||
![]() | |||
[13] | B C. Dhage, “On some nonlinear alternatives of Leray-Schauder type and functonal integral equation,” Archivum Mathematicum, Vol. 42 (2006), No. 1, 11-23. | ||
![]() | |||
[14] | B C. Dhage, “On some variants of Shauder's fixed point principle and application to nonlinear integral equations,” J. Math. Phys. Sci. 25 (1998), 603-611. | ||
![]() | |||
[15] | B C. Dhage, “On a fixed point theorem in Banach algebra with application,” Applied mathematics Letters 18, 2005, 273-280. | ||
![]() | View Article | ||
[16] | B C. Dhage, “Remarks on two fixed pont theorems involving the sum and the product of two operators,” Comput.Math. Appl. 46 (2003) 1779-1785. | ||
![]() | View Article | ||
[17] | B C. Dhage, “On α-condensing mappings in Banach algebra,” Math Student 63 (1994), 146-152. | ||
![]() | |||
[18] | B C. Dhage, “Multivalued mappings and fixed point II”, Tamkang Journal of Mathematics, Volume 37, Number 1 (2006). | ||
![]() | |||
[19] | B C. Dhage, “Local fixed point theory involving three operators in Banach algebra,” Topological Methods in Nonlinear analysis. Volume 24 2004, 377-386. | ||
![]() | View Article | ||
[20] | S. Kakutani, “A generalisation of Brower's fixed point theorems,” Duke Math. J, 8 (1941), 457-459. | ||
![]() | View Article | ||
[21] | W.A. Kirk, B. Sims, “Handbook of Metric fixed point theory,” Kluwer Acad. Publ., Dordrecht, 2001. | ||
![]() | View Article | ||
[22] | D. Kandilakis and N. S. Papageorgiou, On the properties of the Aumann integral with applications to differential inclusions and control systems,” Czechoslovak Math. J. 39 (1989), 1-15. | ||
![]() | |||
[23] | M.Kamenskii, V.Obukhovskii and P.Zecca, “Condensing multivalued maps and Semilinear Differential inclusion in Banach Spaces,” 2001. | ||
![]() | |||
[24] | D. O'Regan, “Fixed point theory for closed multifunctios,” Arch. Math (Brno), 34 (1998), 191-197. | ||
![]() | |||
[25] | E. Zeidler, “Nonlinear Functional Analysis and its application,” Part I Springer Verlag, 1985. | ||
![]() | View Article | ||
[26] | M.Ghiocel, A. Petrusel and G. Petrusel, “Topic in Nonlinear Analyses and application to Matimatical Economics,” Cluj-Napoca 2007. | ||
![]() | |||