Subordination on ultrametric spaces

Using the formalism of continuous-time random walks (CTRW) the authors discuss particle diffusion on ultrametric spaces (UMS). For broad waiting time distributions psi (t) approximately t - alpha -1 the temporal ( alpha ) and the energetic ( gamma ) parameters combine multiplicatively (subordinate): i.e. S(t), the mean number of UMS sites visited, follows a S(t) approximately t alpha gamma law. This mirrors previous findings for CTRW on fractals.