On Hyers-Ulam-Rassias Stability and Hyperstability of Generalized Affine, Quadratic and Drygas Functional Equations
摘要
We investigate the Hyers-Ulam-Rassias stability and hyperstability of the functional equations \(\begin{aligned} f\left[ g(x+\lambda y)\right] &=f(x)+f(y),\\ f\left[ g(x+\lambda y)\right] +f\left[ g(x-\lambda y)\right] &=2f(x)+2\lambda ^2f(y),\\ f\left[ g(x+\lambda y)\right] +f\left[ g(x-\lambda y)\right] &=2f(x)+\lambda ^2[f(y)+f(-y)], \end{aligned}\) in Banach spaces.