INVERTIBLE TIME SERIES

It is a time series represented by this function:

                                                                 

where φ is a sequence of real numbers, B is a lag operator and ε is a sequence of independent identically distributed random variables with zero mean and variance σ2. The function has to be reversible and can be expressed in the form:

                                                                  

where:

                                                         

Editor: Giuliano DI TOMMASO