Nonlinear Analysis 74 (2011) 1436–1444
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Nonlinear Analysis
journal homepage: www.elsevier.com/locate/na
Multivalued generalized nonlinear contractive maps and fixed points
Abdul Latif
a,∗
, Afrah A.N. Abdou
b
a
Department of Mathematics, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia
b
Science Faculty For Girls, King Abdulaziz University, P.O. Box 14884, Jeddah 21434, Saudi Arabia
article info
Article history:
Received 1 August 2010
Accepted 4 October 2010
MSC:
54H25
54C60
Keywords:
Metric space
Fixed point
Hausdorff metric
Multivalued nonlinear contractive map
w-distance
abstract
We introduce some notions of generalized nonlinear contractive maps and prove some
fixed point results for such maps. Consequently, several known fixed point results are
either improved or generalized including the corresponding recent fixed point results
of Ciric [L.B. Ciric, Multivalued nonlinear contraction mappings, Nonlinear Anal. 71
(2009) 2716–2723], Klim and Wardowski [D. Klim, D. Wardowski, Fixed point theorems
for set-valued contractions in complete metric spaces, J. Math. Anal. Appl. 334 (2007)
132–139], Feng and Liu [Y. Feng, S. Liu, Fixed point theorems for multivalued contractive
mappings and multivalued Caristi type mappings, J. Math. Anal. Appl. 317 (2006) 103–112]
and Mizoguchi and Takahashi [N. Mizoguchi, W. Takahashi, Fixed point theorems for
multivalued mappings on complete metric spaces, J. Math. Anal. Appl. 141 (1989)
177–188].
© 2010 Elsevier Ltd. All rights reserved.
1. Introduction and preliminaries
Let (X , d) be a metric space, 2
X
a collection of nonempty subsets of X , and CB(X ) a collection of nonempty closed bounded
subsets of X , Cl(X ) a collection of nonempty closed subsets of X , K (X ) a collection of nonempty compact subsets of X .
For any A, B ∈ CB(X ), let
H(A, B) = max{sup
x∈A
d(x, B), sup
y∈B
d(y, A)},
where d(x, B) = inf
y∈B
d(x, y). H is called the Hausdorff metric induced by d.
An element x ∈ X is called a fixed point of a multivalued map T : X → 2
X
if x ∈ T (x). We denote Fix(T ) ={x ∈ X : x ∈
T (x)}. A sequence {x
n
} in X is called an orbit of T at x
0
∈ X if x
n
∈ T (x
n−1
) for all n ≥ 1.
A map f : X → R is called lower semicontinuous if any sequence {x
n
} ⊂ X with x
n
→ x ∈ X implies that
f (x) ≤ lim inf
n→∞
f (x
n
).
Investigations on the existence of fixed points of multivalued contractions in metric spaces were initiated by Nadler [1].
Using the Hausdorff metric, he established the following multivalued version of the well known Banach contraction
principle.
Theorem 1.1. Let (X , d) be a complete metric space and let T : X → CB(X ) be a map such that for a fixed constant h ∈ (0, 1)
and for each x, y ∈ X,
H(T (x), T (y)) ≤ hd(x, y).
Then Fix(T ) =∅.
∗
Corresponding author. Tel.: +966 2 6952000.
E-mail addresses: alatif@kau.edu.sa, Latifmath@yahoo.com (A. Latif), aabdou@kau.edu.sa (A.A.N. Abdou).
0362-546X/$ – see front matter © 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.na.2010.10.017