On co-Farthest Points in Normed Linear Spaces

In this paper, we consider the concepts co-farthest points innormed linear spaces. At first, we define farthest points, farthest orthogonalityin normed linear spaces. Then we define co-farthest points, co-remotal sets,co-uniquely sets and co-farthest maps. We shall prove some theorems aboutco-farthest points, co-remotal sets. We obtain a necessary and coecient conditionsabout co-farthest points and dual space. Also, we show that everyco-remotal set is co-uniquely set.