0.1 Time Series
A time series is a set of observations \(x_t\) each recorded at a specific time \(t\). The set of observation times is denoted \(T_0\).
A discrete-time time series is one in which the set \(T_0\) of observation times is a discrete set.
A continuous-time time series is one in which observations are recorded continuously over some time interval, such as \(T_0=[0,1]\).