Uniqueness of a martingale-coboundary decomposition of stationary processes
In the limit theory for strictly stationary processes , the decomposition proved to be very useful; here is a bimeasurable and measure preserving transformation an is a martingale difference sequence. We shall study the uniqueness of the decomposition when the filtration of is fixed. The case when the filtration varies is solved in [13]. The necessary and sufficient condition of the existence of the decomposition were given in [12] (for earlier and weaker versions of the results see [7])....