Rend. Circ. Mat. Palermo
DOI 10.1007/s12215-015-0211-0
Weakly ( s, r )-contractive multi-valued operators
Tayyab Kamran
1,2
· Sharafat Hussain
1
Received: 2 February 2015 / Accepted: 8 June 2015
© Springer-Verlag Italia 2015
Abstract In this paper we introduce the notion of weakly (s, r )-contractive multi-valued
operator and establish some fixed point theorems for this operator. Our results generalize the
results of Popescu.
Keywords Multi-valued maps · (s, r )-contraction · Weakly Picard operator
Mathematics Subject Classification 47H10 · 54H25
1 Introduction and preliminaries
The Banach fixed point theorem [1] says that every contraction on a complete metric space
has a unique fixed point. To get an analog result for multi-valued mappings, one has to equip
the powerset of a set with some suitable metric. One such metric is a Hausdorff metric.
The study of fixed points for multi-valued contractions and nonexpansive maps using the
Hausdorff metric was initiated by Markin [5]. Following the Banach contraction principle
Nadler [6] introduced the concept of multi-valued contraction and established that a multi-
valued contraction possesses a fixed point in a complete metric space. Reich [8, 9] generalized
the contractive condition given by Nadler [6]. Rus [10] introduced the notion of a multi-
valued weakly Picard operator. Jleli et al. [2] extended multi-valued weakly Picard operator
in the setting of partial Hausdorff metric spaces. Popescu [7] introduced the notion of (s, r )-
contractive multi-valued operators and showed that they are weakly Picard operators. He
B Tayyab Kamran
tayyabkamran@gmail.com
Sharafat Hussain
sharafat185@gmail.com
1
Department of Mathematics, Quaid-i-Azam University, Islamabad, Pakistan
2
Department of Mathematics, School of Natural Sciences, National University of Sciences
and Technology, H-12, Islamabad, Pakistan
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