Bujosa, Marcos; Brun, Andrés Bujosa; García-Ferrer, … - Facultad de Ciencias Económicas y Empresariales, … - 2013
Although spectral analysis of stationary stochastic processes has solid mathematical foundations, this is not always so for some non-stationary cases. Here, we establish a rigorous mathematical extension of the classic Fourier spectrum to the case in which there are AR roots in the unit circle,...