A limit theory is developed for the least squares estimator for mildly and purely explosive autoregressions under drifting sequences of parameters with autoregressive roots ρn satisfying ρn Ç ρ ∈ (-É, -1] ∪ [1, É) and n (

A limit theory is developed for the least squares estimator for mildly and purely explosive autoregressions under drifting sequences of parameters with autoregressive roots ρn satisfying ρn → ρ ∈ (-∞, -1] ∪ [1, ∞) and n (|ρn| -1) → ∞. Drifting sequences of innovations and...

This paper analyzes the dynamics of the Spanish public debt-GDP ratio during the period 1850-2021. We use recent procedures to test for explosive bubbles under the presence of time-varying volatility (Harvey, Leybourne, Sollis and Taylor, 2016; Harvey, Leybourne and Zu, 2019, 2020; Kurozumi, Skorobotov...

This paper analyzes the dynamics of the Spanish public debt-GDP ratio during the period 1850-2021. We use recent procedures to test for explosive bubbles under the presence of time-varying volatility (Harvey, Leybourne, Sollis and Taylor, 2016; Harvey, Leybourne and Zu, 2019, 2020; Kurozumi, Skorobotov...

An asymptotic theory is given for autoregressive time series with weakly dependent innovations and a root of the form rho_{n} = 1+c/n^{alpha}, involving moderate deviations from unity when alpha in (0,1) and c in R are constant parameters. The limit theory combines a functional law to a...