Effects of Small Delays on Stability and Control
Stabilization and control of partial differential equations through the application of forces on the boundary turns out to be very important in applications. When the boundary forces are applied with no delays there is a rather complete theory. In applications, however, it is very likely that time delays will occur when applying the boundary forces. So it is of vital importance to understand the sensitivity with respect to small time delays and problems of this type have attracted a lot of attention, especially in the engineering literature. In this paper we shall explain the underlying mechanisms and the important role difference equations and almost periodic functions are playing in these results.