Fixed Point Theory and Applications
Volume 2007 (2007), Article ID 19745, 7 pages
doi:10.1155/2007/19745
  
     
          
          Diametrically contractive multivalued mappings
          
            S. Dhompongsa
             and H. Yingtaweesittikul
          
          Department of Mathematics, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
          
          Abstract
Diametrically contractive mappings on a complete metric space are introduced by V. I. Istratescu. We extend and generalize this idea to multivalued mappings. An easy example shows that our fixed point theorem is more applicable than a former one obtained by H. K. Xu. A convergence theorem of Picard iteratives is also provided for multivalued mappings on hyperconvex spaces, thereby extending a Proinov's result.