Lee, JRPark, CAlaca, CShin, DY2025-04-102025-04-101521-1398http://hdl.handle.net/20.500.14701/41510Using the fixed point method, we prove the Hyers-Ulam stability of the orthogonally additive-quadratic functional equation 2f (x+y/2) + 2f (x-y/2) = 3/2 f(x) - 1/2 f(y) + 1/2f(-y) (0.1) for all x, y with x perpendicular to y, in non-Archimedean Banach spaces. Here perpendicular to is the orthogonality in the sense of Ratz.EnglishArticle1572-9206