A Note on Mixing in High Dimensional Time Series
Various mixing conditions have been imposed on high dimensional time series, including the strong mixing ($α$-mixing), maximal correlation coefficient ($ρ$-mixing), absolute regularity ($β$-mixing), and $ϕ$-mixing. $α$-mixing condition is a routine assumption when studying autoregression models. $ρ$-mixing can lead to $α$-mixing. In this paper, we prove a way to verify $ρ$-mixing under a high-dimensional triangular array time series setting by using the Pearson's $ϕ^2$, mean square contingency. Vector autoregression model VAR(1) and vector autoregression moving average VARMA(1,1) are proved satisfying $ρ$-mixing condition based on low rank setting.
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