The problem of localization of interacting particles leads me to consider the question of competition between alternative propagation channels, which can be studied in great detail in the form of a single particle problem with two parallel, parametrically different, coupled channels. One could ask what happens to the localization properties when a less localized lattice is coupled to a more localized one? Will the less localized one dominate the localization of the system or the more localized? The qualitative answer to this question depends on the dimensionality of the system....