Bull. Korean Math. Soc. 2008 Vol. 45, No. 1, 39-44 Printed March 1, 2008
Won Keun Min Kangwon National University
Abstract : In this paper, we introduce the concepts of preconvexity neighborhoods, $c$-concave functions. We study some properties for $c$-convex functions, and characterize $c$-convex functions and $c$-concave functions by using the preconvexity neighborhoods.
Keywords : preconvexity, preconvex neighborhood, $c$-concave function