On Linear Operators that Preserve BJ-Orthogonality in 2-Normed Spaces

Let X be a real 2-Banach space. We follow Gunawan, Mashadi, Gemawati, Nursupiamin and Siwaningrum in saying that x is orthogonal to y if there exists a subspace V of X with codim(V) = 1 such that parallel to x +lambda y,z parallel to >= parallel to x,z parallel to for every z is an element of V and lambda is an element of R. In this paper, we prove that every linear mapping T : X -> X which preserve orthogonality is a 2-isometry multiplied by a constant.