Abstract
In this paper, we determine all functions ƒ, defined on a field K (belonging to a certain class) and taking values in an abelian group, such that the quadratic difference ƒ(x + y) + ƒ(x − y) − 2ƒ(x) − 2ƒ(y) depends only on the product xy for all x, y ∈ K. Using this result, we find the general solution of the functional equation ƒ1(x + y) + ƒ2(x − y) = ƒ3(x) + ƒ4(y) + g(xy).
Similar content being viewed by others
References
J. Aczél, J.K. Chung and C.T. Ng, Symmetric second differences in product form on groups.In Topics in mathematical analysis. World Scientific Publ. Co., 1989, 1-22.
J. Aczél and J. Dhombres, Functional Equations in Several Variables. Cambridge University Press, Cambridge, 1989.
J.K. Chung, B.R. Ebanks, C.T. Ng, P.K. Sahoo and W.B. Zeng, On a functional equation of Abel. Results in Mathematics., 26 (1994), 241–252.
J. Dhombres, Autour de ƒ(x)ƒ(y) − ƒ(xy). Aequationes Math. 27 (1984), 231–235.
B.R. Ebanks, PL. Kannappan, and P.K. Sahoo, Cauchy differences that depend on the product of arguments. Glasnik Matematicki, 27(47) (1992), 251–261.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Chung, J.K., Ebanks, B.R., Ng, C.T. et al. Quadratic Differences that Depend on the Product of Arguments. Results. Math. 31, 53–74 (1997). https://doi.org/10.1007/BF03322151
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03322151