Integration and approximation of multivariate functions: average case complexity with isotropic Wiener measure

We study the average case complexity of multivariate integration and $L_2$ function approximation for the class $F=C([0,1]^d)$ of continuous functions of $d$ variables. The class $F$ is endowed with the isotropic Wiener measure (Brownian motion in Levy's sense). Furthermore, for both problems, only function values are used as data.