• Title/Summary/Keyword: Ulam stability

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STABILITY OF THE FUNCTIONAL EQUATIONS RELATED TO A MULTIPLICATIVE DERIVATION

  • Kim, Hark-Mahn;Chang, Ick-Soon
    • Journal of applied mathematics & informatics
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    • v.11 no.1_2
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    • pp.413-421
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    • 2003
  • In this paper, using an idea from the direct method of Hyers and Ulam, we investigate the situations so that the Hyers-Ulam-Rassias stability of the functional equation $g(x^2)\;=\;2xg(x)$ is satisfied.

ON THE GENERALIZED HYERS-ULAM STABILITY OF A CUBIC FUNCTIONAL EQUATION

  • Jun, Kil-Woung;Lee, Sang-Baek
    • Journal of the Chungcheong Mathematical Society
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    • v.19 no.2
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    • pp.189-196
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    • 2006
  • The generalized Hyers-Ulam stability problems of the cubic functional equation f(x + y + z) + f(x + y - z) + 2f(x - y) + 4f(y) = f(x - y + z) + f(x - y - z) +2f(x + y) + 2f(y + z) + 2f(y - z) shall be treated under the approximately odd condition and the behavior of the cubic mappings and the additive mappings shall be investigated. The generalized Hyers-Ulam stability problem for functional equations had been posed by Th.M. Rassias and J. Tabor [7] in 1992.

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HYERS-ULAM STABILITY OF MAPPINGS FROM A RING A INTO AN A-BIMODULE

  • Oubbi, Lahbib
    • Communications of the Korean Mathematical Society
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    • v.28 no.4
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    • pp.767-782
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    • 2013
  • We deal with the Hyers-Ulam stability problem of linear mappings from a vector space into a Banach one with respect to the following functional equation: $$f\(\frac{-x+y}{3}\)+f\(\frac{x-3z}{3}\)+f\(\frac{3x-y+3z}{3}\)=f(x)$$. We then combine this equation with other ones and establish the Hyers-Ulam stability of several kinds of linear mappings, among which the algebra (*-) homomorphisms, the derivations, the multipliers and others. We thus repair and improve some previous assertions in the literature.

HYERS-ULAM-RASSIAS STABILITY OF ISOMORPHISMS IN C*-ALGEBRAS

  • Park, Choonkil
    • Journal of the Chungcheong Mathematical Society
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    • v.19 no.2
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    • pp.159-175
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    • 2006
  • This paper is a survey on the Hyers-Ulam-Rassias stability of the Jensen functional equation in $C^*$-algebras. The concept of Hyers-Ulam-Rassias stability originated from the Th.M. Rassias' stability theorem that appeared in his paper: On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72 (1978), 297-300. Its content is divided into the following sections: 1. Introduction and preliminaries. 2. Approximate isomorphisms in $C^*$-algebras. 3. Approximate isomorphisms in Lie $C^*$-algebras. 4. Approximate isomorphisms in $JC^*$-algebras. 5. Stability of derivations on a $C^*$-algebra. 6. Stability of derivations on a Lie $C^*$-algebra. 7. Stability of derivations on a $JC^*$-algebra.

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ON THE STABILITY OF THE GENERALIZED G-TYPE FUNCTIONAL EQUATIONS

  • KIM, GWANG-HUI
    • Communications of the Korean Mathematical Society
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    • v.20 no.1
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    • pp.93-106
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    • 2005
  • In this paper, we obtain the generalization of the Hyers-Ulam-Rassias stability in the sense of Gavruta and Ger of the generalized G-type functional equations of the form $f({{\varphi}(x)) = {\Gamma}(x)f(x)$. As a consequence in the cases ${\varphi}(x) := x+p:= x+1$, we obtain the stability theorem of G-functional equation : the reciprocal functional equation of the double gamma function.