The aim of the current manuscript is to prove the Hyers-Ulam stability of supremum, infimum and multiplication preserving functional equations in Banach f -algebras. In fact, by using the direct method and the fixed point method, the Hyers-Ulam stability of the functional equations is proved.

中文翻译：

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Banach f-代数中格泛函方程的近似解。

本手稿的目的是证明Banach f代数中至上，无穷和乘积保函数方程的Hyers-Ulam稳定性。实际上，通过直接法和不动点法，证明了函数方程的Hyers-Ulam稳定性。