RDP 9810: The Distribution and Measurement of Inflation Equation

\begin{array}{l} t < k_{1} & j = 1 \\ k_{1} \leq t < k_{2} & j = 2 \\ k_{2} \leq t < k_{3} & j = 3 \\ k_{3} \leq t & j = 4 \end{array}