A DT signal is a function u : Z+ 7→ R, where Z+ = {0, 1, 2, . . . } is the set of all nonnegative integers. In other words, an n-dimensional DT signal is a semi-infinite sequence u = (u(0), u(1), u(2), . . . ) of vectors from R. As a shortcut notation, we will use ` (or simply ` when n = 1) for the set of all n-dimensional DT signals. In this definition of DT signals, the set Z+ acts as the set...

We consider a scenario in which our observable universe is a 3-dimensional surface (3-brane) living in extra dimensions with a warped geometry. We show that “lensed” density perturbations from other branes serve as possible seeds for structure formation on our observable brane (without inflation), and, in addition, provide constraints on braneworld scenarios with warped bulk geometry. Due to th...