Islamic Azad University, Rasht BranchIranian Journal of Optimization2588-572306220140701Unweighted p-center problem on extended stars737744526830ENJafar FathaliDepartment of Mathematics, Shahrood University of Technology, University Blvd., Shahrood, IranNader Jafari RadDepartment of Mathematics, Shahrood University of Technology, University Blvd., Shahrood, IranSadegh Rahimi SherbafDepartment of Mathematics, Shahrood University of Technology, University Blvd., Shahrood, IranJournal Article20140120An extended star is a tree which has only one vertex with degree larger than two. The -center problem in a graph asks to find a subset of the vertices of of cardinality such that the maximum weighted distances from to all vertices is minimized. In this paper we consider the -center problem on the unweighted extended stars, and present some properties to find solution.http://ijo.iaurasht.ac.ir/article_526830_37ef51736b0d3ec69e1bab922522c3ec.pdf