Изменения

\begin{document}{rcl}$X_1 X_2 X_3 \ldots X_n$ & $\to$&$ Z_1 X_2 X_3 \ldots X_n,$\\$Z_1 X_2 X_3 \ldots X_n$ & $\to$& $Z_1 Z_2 X_3 \ldots X_n,$\\$Z_1 Z_2 X_3 \ldots X_n$ & $\to$& $Z_1 Z_2 Z_3 \ldots X_n,$\\&$\ldots$&vdots\\$Z_1 Z_2 \ldots Z_{n-1} X_n$ &$\to$& $Z_1 Z_2 \ldots Z_{n-1} Z_n,$\\$Z_1 Z_2 Z_3 \ldots Z_n$ &$\to$& $Y_1 Z_2 Z_3 \ldots Z_n,$\\$Y_1 Z_2 Z_3 \ldots Z_n$ &$\to$& $Y_1 Y_2 Z_3 \ldots Z_n,$\\$Y_1 Y_2 Z_3 \ldots Z_n$ &$\to$& $Y_1 Y_2 Y_3 \ldots Z_n,$\\&$\ldots$&vdots\\$Y_1 Y_2 Y_3 \ldots Y_{n-1} Z_n$&$\to$& $Y_1 Y_2 Y_3 \ldots Y_{n-1} Y_n \ldots Y_m.$\\\end{document}