Convergence and divergence of wavelet series: multifractal aspects

We study the convergence and divergence of the wavelet expansion of a function in a Sobolev or a Besov space from a multifractal point of view. In particular, we give an upper bound for the Hausdorff and for the packing dimension of the set of points where the expansion converges (or diverges) at a given speed, and we show that, generically, these bounds are optimal.