Editing Periodic function (section)

===Bloch-periodic functions===
A further generalization appears in the context of [[Bloch's theorem]]s and [[Floquet theory]], which govern the solution of various periodic differential equations.  In this context, the solution (in one dimension) is typically a function of the form
:<math>f(x+P) = e^{ikP} f(x) ~,</math>
where <math>k</math> is a real or complex number (the ''Bloch wavevector'' or ''Floquet exponent'').  Functions of this form are sometimes called '''Bloch-periodic''' in this context.   A periodic function is the special case <math>k=0</math>, and an antiperiodic function is the special case <math>k=\pi/P</math>. Whenever <math>k P/ \pi</math> is rational,  the function is also periodic.