Изменения

\mathrm{f}(x) & y = 0\\

\mathrm{g}(x, y-1,\mathrm{R}\langle{}\mathrm{f},\mathrm{g}\rangle(x, y-1)) & y > 0

<tex>=\left\{\begin{array} {ll}

x & y = 0\\

\mathrm{N}(\mathrm{R}(x, y-1)) & y > 0

<tex>=\left\{\begin{array} {ll}