Korean Journal of Mathematics

The Kangwon-Kyungki Mathematical Society (강원경기수학회)
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FUNCTIONAL EQUATIONS IN ORTHOGONALITY SPACES

  • Received : 2012.01.05
  • Accepted : 2012.03.05
  • Published : 2012.03.30
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Abstract

Using fixed point method, we prove the Hyers-Ulam stability of the orthogonally additive functional equation (0.1) $f(2x+y)=2f(x)+f(y)$ and of the orthogonally quadratic functional equation (0.2) $2f(\frac{x}{2}+y)+2f(\frac{x}{2}-y)=f(x)+4f(y)$ for all $x$, $y$ with $x{\perp}y$ in orthogonality spaces.

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References

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