  In this note, we propose a method to under-approximate finite-time reachable
sets and tubes for a class of continuous-time linear uncertain systems. The
class under consideration is the linear time-varying (LTV) class with
integrable time-varying system matrices and uncertain initial and input values
belonging to known convex compact sets. The proposed method depends upon the
iterative use of constant-input reachable sets which results in convergent
under-approximations in the sense of Hausdorff distance. We illustrate our
approach through two numerical examples.
