Abstract and Applied Analysis
Volume 2008 (2008), Article ID 135237, 10 pages
doi:10.1155/2008/135237
Research Article
A Functional Equation Originating from Elliptic Curves
1National Institute for Mathematical Sciences, 385-16 Doryong-Dong, Yuseong-Gu, 305-340 Daejeon, South Korea
2College of Liberal Arts, Kyung Hee University, 449-701 Yongin, South Korea
Received 17 November 2007; Revised 1 February 2008; Accepted 5 April 2008
Academic Editor: John Rassias
Copyright © 2008 Won-Gil Park and Jae-Hyeong Bae. 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.
Abstract
We obtain the general solution and the stability of the functional
equation
f(x+y+z,u+v+w)+f(x+y−z,u+v+w)+2f(x,u−w)+2f(y,v−w)=f(x+y,u+w)+f(x+y,v+w)+f(x+z,u+w)+f(x−z,u+v−w)+f(y+z,v+w)+f(y−z,u+v−w).
The function f(x,y)=x3+ax+b−y2 having level curves as elliptic curves is a solution of the above functional equation.