Jh. Bae et Kw. Jun, On the generalized Hyers-Ulam-Rassias stability of an n-dimensional quadratic functional equation, J MATH ANAL, 258(1), 2001, pp. 183-193
m this paper we investigate the generalized Hyers-Ulam-Rassias stability of
an n-dimensional quadratic functional equation,
f(Sigma (n)(i=1) xi) + Sigma (1 less than or equal toi <j less than or equa
l ton) f(x(i) - x(j)) = n Sigma (n)(i=1) f(x(i)) (n greater than or equal t
o 2).
(C) 2000 Academic Press.