Quasiperiodic motion

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In mathematics and theoretical physics, quasiperiodic motion is in rough terms the type of motion executed by a dynamical system containing a finite number (two or more) of incommensurable frequencies.^[1]

That is, if we imagine that the phase space is modelled by a torus T (that is, the variables are periodic like angles), 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

is the type of function (continuous, say) obtained from a function on T, by means of a curve

R → T

which is linear (when lifted from T to its covering

is something distinct from this.)

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.

References

See also

• Quasiperiodicity