%
% This LaTeX environment is for printing subequations.
% To use this environment, include in the \documentstyle
% header a command to load in the .sty file containing this macro.
%
% Example:
%
% \documentstyle[11pt,subeqn]{article}
%
% \begin{subequations}
% \begin{eqnarray}
% & & [equation] \label{1.1a} \\
% & & [equation] \label{1.1b}
% \end{eqnarray}
% \label{1.1}
% \end{subequations}
%
% You can then refer to either 1.1, 1.1a, or 1.1b.
%
% Modified : June 8, 1989. You can now reference either individual
% equations in the subequations environment, or all of
% them. If you use a \label command immediately after the
% \begin{subequations} command, then a reference to that
% label will generate a reference to the equation number
% without the alphabetic extension.
%
% Modified : 16 - january - 1989 by Johannes Braams ( BRAAMS@HLSDNL5)
% Added \global\@ignoretrue in the definition of
% \endsubequations in order to prevent a spurious space
% at the beginning of the next text-line. Also added %'s
% at the end of each command-line for the same reasons.
%
%%%----------------------------------------------------------------
%%% File: subeqn.sty
%%% The subequations environment %%%
%
% Within the subequations environment, the only change is that
% equations are labeled differently. The number stays the same,
% and lower case letters are appended. For example, if after doing
% three equations, numbered 1, 2, and 3, you start a subequations
% environmment and do three more equations, they will be numbered
% 4a, 4b, and 4c. After you end the subequations environment, the
% next equation will be numbered 5.
%
% Both text and equations can be put inside the subequations
% environment.
% If you make any improvements, I'd like to hear about them.
%
%
\newtoks\@stequation
\def\subequations{\refstepcounter{equation}%
\edef\@savedequation{\the\c@equation}%
\@stequation=\expandafter{\theequation}% %only want \theequation
\edef\@savedtheequation{\the\@stequation}% %expanded once
\edef\oldtheequation{\theequation}%
\setcounter{equation}{0}%
\def\theequation{\oldtheequation\alph{equation}}}%
\def\endsubequations{%
\setcounter{equation}{\@savedequation}%
\@stequation=\expandafter{\@savedtheequation}%
\edef\theequation{\the\@stequation}\global\@ignoretrue}
%%%----------------------------