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  • P-ISSN1226-0657
  • E-ISSN2287-6081
  • KCI

CHARACTERIZATIONS OF AN INNER PRODUCT SPACE BY GRAPHS

Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics / Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics, (P)1226-0657; (E)2287-6081
2009, v.16 no.4, pp.359-367
Lin, C.S.

Abstract

The graph of the parallelogram law is well known, which gives rise to the characterization of an inner product space among normed linear spaces [6]. In this paper we will sketch graphs of its deformations according to our previous paper [7, Theorem 3.1 and 3.2]; each one of which characterizes an inner product space among normed linear spaces. Consequently, the graphs of some classical characterizations of an inner product space follow easily.

keywords
inner product space, Jordan-Neumann condition, parallelogram law, Ficken's condition, Oman's condition, law of cosines, Carlsson's condition, Day's codition

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Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics