Advances in Difference Equations
Volume 2009 (2009), Article ID 256165, 10 pages
doi:10.1155/2009/256165
A Fixed Point Approach to the Stability of a Quadratic Functional Equation in C∗-Algebras
Mohammad B. Moghimi1
, Abbas Najati1
and Choonkil Park3
1Department of Mathematics, Faculty of Sciences, University of Mohaghegh Ardabili, 56199-11367 Ardabil, Iran
3Department of Mathematics, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea
Abstract
We use a fixed point method to investigate the stability problem of the quadratic functional equation f(x+y)+f(x−y)=2f(xx∗+yy∗) in C∗-algebras.