Quasiperiodic motion
In mathematics and theoretical physics, quasiperiodic motion is in rough terms the type of motion executed by a dynamical system containing a finite number of incommensurable frequencies.
That is, if we imagine that the phase space is modelled by a torus T, the trajectory of the system is modelled by a curve on T that wraps around the torus without ever exactly coming back on itself.
A quasiperiodic function on the real line is the type of function obtained from a function on T, by means of a curve
which is linear, by composition. It is therefore oscillating, with a finite number of underlying frequencies.
The theory of almost periodic functions is, roughly speaking, for the same situation but allowing T to be a torus with an infinite number of dimensions.
