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A Common Generalization of Functional Equations Characterizing Normed and Quasi-Inner-Product Spaces

Published online by Cambridge University Press:  20 November 2018

B. R. Ebanks
Affiliation:
Department of Mathematics University of Louisville Louisville, Kentucky 40292 U.S.A.
PL. Kannappan
Affiliation:
Department of Pure Mathematics University of Waterloo Waterloo, Ontario N2L 3G1
P. K. Sahoo
Affiliation:
Department of Mathematics University of Louisville Louisville, Kentucky 40292 U.S.A.
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Abstract

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We determine the general solutions of the functional equation for ƒi: G → F (i = 1,2,3,4), where G is a 2-divisible group and F is a commutative field of characteristic different from 2. The motivation for studying this equation came from a result due to Dry gas [4] where he proved a Jordan and von Neumann type characterization theorem for quasi-inner products. Also, this equation is a generalization of the quadratic functional equation investigated by several authors in connection with inner product spaces and their generalizations. Special cases of this equation include the Cauchy equation, the Jensen equation, the Pexider equation and many more. Here, we determine the general solution of this equation without any regularity assumptions on ƒi.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1992

References

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