Abstract. We study Sobolev spaces on the n−dimensional unit ball B n (1) endowed with a parameter-depending Finsler metric F a , a ∈ [0, 1], which interpolates between the Klein metric (a = 0) and Funk metric (a = 1), respectively. We show that the standard Sobolev space defined on the Finsler manifold (B n (1), F a ) is a vector space if and only if a ∈ [0, 1). Furthermore, by exploiting variational arguments, we provide non-existence and existence results for sublinear elliptic problems on (B n (1), F a ) involving the Finsler-Laplace operator whenever a ∈ [0, 1).