What is periodic wave function?



A wave function (x, f) which satisfied the periodicity condtions of position and time is called a periodic wave function, i.e.,
(i) y(x + m$\lambda $t) = y(x, t)
(ii) y(x, t + nT) = y(x, t)
where $\lambda $ = wavelength of wave, T = period of the wave, n and m are integers.