It is well known that traditional inference do not apply when the spectral density of a stationary process vanishes for some frequency. This paper examines some properties of several new non parametric tests of this hypothesis which have been recently proposed by Lacroix (1999). These tests...

Non parametric and parametric estimation for the spectral density of a stationary process is a well-known topic, except when the spectrum vanishes for some frequency. Indeed, for this frequency, the limit law degenerates, and traditional inference no longer applies. The paper introduces non...

In this article, we analyze the US short term real interest rate series for the last five decades in the framework of a M-SETAR model (Momentum - Self Exciting Threshold Auto-Regressive). With the aim of disentangling the non-linearity from the non-stationarity cases, we use threshold...

The purpose of this article is to study the trends in per capita productivity in several major industrialised countries. The analysis is first based on annual data over a long period spanning the entire 20th century for the United States, France and the United Kingdom. Productivity trends are...