Abstract
In this paper we investigate the problem of the Hyers-Ulam stability of the generalized quadratic functional equation $$f(x+y)+f(x-y)=g(x)+g(y),$$ where $f,g$ are functions defined on a group with values in a linear topological space.
Citation
M. Adam. M. Czerwik. "On the stability of the quadratic functional equation in topological spaces." Banach J. Math. Anal. 1 (2) 245 - 251, 2007. https://doi.org/10.15352/bjma/1240336223
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