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

LINEAR MAPPINGS, QUADRATIC MAPPINGS ANDCUBIC MAPPINGS IN NORMED SPACES

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
2003, v.10 no.3, pp.185-192
Park, Chun-Gil
Wee, Hee-Jung

Abstract

It is shown that every almost linear mapping <TEX>$h{\;}:{\;}X{\;}{\rightarrow}{\;}Y$</TEX> of a complex normed space X to a complex normed space Y is a linen. mapping when h(rx) = rh(x) (r > 0,<TEX>$r\;{\neq}\;1$</TEX) holds for all <TEX>$x{\;}{\in}{\;}X$</TEX>, that every almost quadratic mapping <TEX>$h{\;}:{\;}X{\;}{\rightarrow}{\;}Y$</TEX> of a complex normed space X to a complex normed space Y is a quadratic mapping when <TEX>$h(rx){\;}={\;}r^2h(x){\;}(r{\;}>{\;}0,r\;{\neq}\;1)$</TEX> holds for all <TEX>$x{\;}{\in}{\;}X$</TEX>, and that every almost cubic mapping <TEX>$h{\;}:{\;}X{\;}{\rightarrow}{\;}Y$</TEX> of a complex normed space X to a complex normed space Y is a cubic mapping when <TEX>$h(rx){\;}={\;}r^3h(x){\;}(r{\;}>{\;}0,r\;{\neq}\;1)$</TEX> holds for all <TEX>$x{\;}{\in}{\;}X$</TEX>.

keywords
liner mapping, quadratic mapping, cubic mapping, stability

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