Mathematica Bohemica, Vol. 142, No. 4, pp. 337-344, 2017
Approximate tri-quadratic functional equations via Lipschitz conditions
Ismail Nikoufar
Received February 17, 2016. First published January 26, 2017.
Abstract: In this paper, we consider Lipschitz conditions for tri-quadratic functional equations. We introduce a new notion similar to that of the left invariant mean and prove that a family of functions with this property can be approximated by tri-quadratic functions via a Lipschitz norm.
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Affiliations: Ismail Nikoufar, Department of Mathematics, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran, e-mail: nikoufar@pnu.ac.ir
