Department of Mathematical Education, Dankook University, 126 Jukjeon, Suji, Yongin, Gyeonggi 448-701, South Korea
Academic Editor: Patricia J. Y. Wong
Copyright © 2010 Dongseung Kang. 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 investigate the generalized Hyers-Ulam-Rassias stability problem in quasi--normed spaces and then the stability by using a subadditive function for the generalized quartic function such that , where , , , for all .