In this paper we develop a regime switching model which can generate long memory (fractional integration) in each of the regime states. This property is relevant in a number of cases. For instance, the deregulated market for electricity power in the Nordic countries is characterized by...

In this paper we propose a model selection strategy for a univariate periodic autoregressive time series which involves tests for one or more unit roots and for parameter restrictions corresponding to seasonal unit roots and multiple unit roots at the zero frequency. Examples of models that are...

This paper provides a survey of the recent literature dealing with I(2) variables in economic time series, that is, processes that require to be differenced twice in order to become stationary. With reference to particular models intuition is provided of why I(2) and polynomial cointegration are...

European labour markets are in a state of flux due to the changing market situation induced by international integration. This process affects wage formation through more fierce product market competition and increased mobility of jobs. This development is by some observers taken to enforce...