Journal of Inequalities and Applications
Volume 2007 (2007), Article ID 41820, 13 pages
Research Article

Functional Inequalities Associated with Jordan‐von Neumann‐Type Additive Functional Equations

Choonkil Park,1 Young Sun Cho,2 and Mi-Hyen Han2

1Department of Mathematics, Hanyang University, Seoul 133‐791, South Korea
2Department of Mathematics, Chungnam National University, Daejeon 305‐764, South Korea

Received 27 September 2006; Accepted 1 November 2006

Academic Editor: Sever S. Dragomir

Copyright © 2007 Choonkil Park et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We prove the generalized Hyers‐Ulam stability of the following functional inequalities: ||f(x)+f(y)+f(z)||||2f((x+y+z)/2)||, ||f(x)+f(y)+f(z)||||f(x+y+z)||, ||f(x)+f(y)+2f(z)||||2f((x+y)/2+z)|| in the spirit of the Rassias stability approach for approximately homomorphisms.