We propose exible models for multivariate realized volatility dynamics which involve generalizations of the Box …

This paper generalises Boswijk and Zu (2018)'s adaptive unit root test for time series with nonstationary volatility to … resulting likelihood ratio test statistic. We find that under suitable conditions, adaptation with respect to the volatility … process is possible, in the sense that nonparametric volatility matrix estimation does not lead to a loss of asymptotic local …