Abstract and Applied Analysis
Volume 2009 (2009), Article ID 360432, 17 pages
doi:10.1155/2009/360432
Stability of the Jensen-Type Functional Equation in C∗-Algebras: A Fixed Point Approach
Choonkil Park1
and John Michael Rassias2
1Department of Mathematics, Hanyang University, Seoul 133-791, South Korea
2Pedagogical Department E.E., National and Capodistrian University of Athens, 4 Agamemnonos Street, Aghia Paraskevi, Athens 15342, Greece
Abstract
Using fixed point methods, we prove the generalized Hyers-Ulam stability of homomorphisms in C∗-algebras and Lie C∗-algebras and also of derivations on C∗-algebras and Lie C∗-algebras for the Jensen-type functional equation f((x+y)/2)+f((x−y)/2)=f(x).