A Short Introduction to Control Theory, Part II
Christoph Kawan

In the second part of the introduction, the basic properties of control
sets are explained, which are the maximal regions of complete approximate
controllability in the state space of a control system. Moreover, the
control flow of a control-affine system is introduced, which is a skew
product flow built from the solutions of the differential equation and the
shift flow on the set of control functions. In particular, we will see how
the dynamical properties of this flow are related to the control-theoretic
properties of the underlying control system.