are attached
to each point of phase space.

The &quot;strategy&quot; or &quot;policy problem&quot; of a controller is to pick out one of these
vectors to actualize at each point in accord with reaching a given target or
for the sake of satisfying a given property.

An individual control system is specified by the information that is attached
to each dynamic point, defining a subset of the tangent space at that point.
This pointwise subset is called &quot;the indicatrix of permissible velocities&quot;
by (Ar