%% %% The LaTeX Companion, 2ed (second printing August 2004) %% %% Example 8-2-29 on page 485. %% %% Copyright (C) 2004 Frank Mittelbach, Michel Goossens, %% Johannes Braams, David Carlisle, and Chris Rowley %% %% It may be distributed and/or modified under the conditions %% of the LaTeX Project Public License, either version 1.3 %% of this license or (at your option) any later version. %% %% See http://www.latex-project.org/lppl.txt for details. %% \documentclass{ttctexa} \pagestyle{empty} \setcounter{page}{6} \setlength\textwidth{135.0pt} \StartShownPreambleCommands \usepackage{amsmath} \StopShownPreambleCommands \begin{document} \begin{subequations} \label{eq:1} \begin{align} f &= g \label{eq:1A} \\ f' &= g' \label{eq:1B} \\ \mathcal{L}f &= \mathcal{L}g \label{eq:1C} \end{align} \end{subequations} \begin{subequations} \label{eq:2} \renewcommand\theequation{\theparentequation\roman{equation}} \begin{align} f &= g \label{eq:2A} \\ f' &= g' \label{eq:2B} \\ \mathcal{L}f &= \mathcal{L}g + K \label{eq:2C} \end{align} \end{subequations} Note the relationship between~\eqref{eq:1} and~\eqref{eq:2}: only~\ref{eq:1C} and~\ref{eq:2C} differ. \end{document}