The stability problem of functional equations originated from a question of Ulam 1 concerning the stability of group homomorphisms. Hyers 2 gave a first affirmative partial answer to the question of Ulam for Banach spaces. Hyers’s theorem was generalized by Aoki 3 for additive mappings. In 1978, Rassias 4 generalized Hyers theorem by obtaining a unique linear mapping near an approximate additiv...

It is shown that the set of all paraperspective images with arbitrary reference point and the set of aane images of a 3-D object are identical. Consequently, all uncalibrated paraper-spective images of an object can be constructed from a 3-D model of the object by applying an aane transformation to the model and every aane image of the object represents some uncalibrated paraperspective image o...

The Hyers–Ulam–Rassias stability of the conditional quadratic functional equation of Pexider type f (x+y)+f (x−y) = 2g(x)+2h(y), x ⊥ y is proved where ⊥ is the orthogonality in the sense of Rätz.