|   |  |  |   | 
Chapter 9
-
World in a mirror
   | 
|  |  |  |  | Symmetries simplify the dynamics in a beautiful way:
If dynamics is invariant under a set of
discrete symmetries,  it can be reduced to dynamics
within the fundamental domain.
Families of symmetry-related cycles
are replaced by fewer and often much shorter
"relative" cycles. | 
        |   |  |  |   | 
Chapter 10
-
Relativity for cyclists
   | 
|  |  |  |  | If the symmetry is continuous, the dynamics is reduced to a
lower-dimensional desymmetrized system by symmetry reduction.
We describe how to do this by `slicing' the group orbits. |