The aim of this paper is to give a relatively simple, usable sufficient and necessary condition to the regularity of generic time series. Also, this condition is used to show how a regular process can be approximated by a lower rank \emph{regular} process.

翻译：本文件的目的是为通用时间序列的正常性提供一个相对简单、可用、足够和必要的条件。此外,这一条件还用来说明一个经常程序如何被较低级别的\emph{经常}程序所近似。