Multiline equations are obtained by using the
begin
eqnarray
, end
eqnarray
format.
Use the nonumber
command at the end of each line where you do not want a number:
\begin{equation}
\left\{\openone234567890abc123\alpha\beta\gamma\delta%
1234556\alpha\beta{1\sum^{a}_{b}\over A^2}\right\}\label{one},
\end{equation}
Note the open one in Eq.\ (\ref{one}).
If the equation is a little wider, the equation number automatically
moves down to the next line:
\begin{equation}
\left\{abc1234567890abc1234\alpha\beta\gamma\delta1234556\alpha\beta%
{1\sum^{a}_{b}\over A^2}abc1234567890abc1234\alpha\beta\gamma\delta%
1234556\alpha\beta{1\sum^{a}_{b}\over A^2}\right\}.
\end{equation}
When the \btt{label} command is used [cf. input for Eq. (\ref{one})],
the equation can be referred to in text without your knowing the
equation number that \TeX\ will assign to it.
Math will be flush left by default, in OSA submissions.
It should allow longer equations to be displayed before line numbers
are displayed below.
\begin{equation}
\left\{ab12345678abc123456abcdef\alpha\beta\gamma\delta%
1234556\alpha\beta{1\sum^{a}_{b}\over A^2}\right\},
\end{equation}
\begin{equation}
\epsilon^\ast_\mu(p)\to c(V)D_V \sum_\tau c^f_\tau \bar
u(f)P_\tau \gamma_\mu v( \bar f)\;
[\epsilon_jl_i\epsilon_i]_{\sigma_1}\chi_{\sigma_1}(p_1)\;.
\end{equation}
If you have a single-line equation that you don't want
numbered, you can use the \btt{[}, \btt{]} format:
\[g^+g^+ \rightarrow g^+g^+g^+g^+ \dots ~,~~q^+q^+\rightarrow
q^+g^+g^+ \dots ~. \]
\subsubsection{Multiline equations}
Multiline equations are obtained by using the
\btt{begin$\{$eqnarray$\}$}, \btt{end$\{$eqnarray$\}$} format.
Use the \btt{nonumber}
command at the end of each line where you do not want a number:
\begin{eqnarray}
{\cal M}=&&ig_Z^2(4E_1E_2)^{1/2}(l_i^2)^{-1}
\delta_{\sigma_1,-\sigma_2}
(g_{\sigma_2}^e)^2\chi_{-\sigma_2}(p_2)\nonumber\\
&&\times [\epsilon_jl_i\epsilon_i]_{\sigma_1}\chi_{\sigma_1}(p_1), \\
\sum \vert M^{\rm viol}_g \vert ^2&=&g^{2n-4}_S(Q^2)~N^{n-2}
(N^2-1)\nonumber \\
& &\times \left( \sum_{i<j}\right)
\sum_{\rm perm}
{1 \over S_{12}}
{1 \over S_{12}}\sum_\tau c^f_\tau~.
\end{eqnarray}
If you wish to set a multiline equation without any line numbers,
you can use the \begin{eqnarray*},
\end{eqnarray*} format:
To obtain numbers not normally produced by the automatic numbering,
use the \eqnum{#1} command, where #1 is the desired
equation number. For example, to get an equation number of
(2.7
),
A few notes on \eqnum.
The \eqnum must come before the \label, if any.
The numbering set with \eqnum is transparent to the
automatic numbering in REVTeX; therefore
you must know the number ahead of time and must make
sure that the number set with \eqnum stays in step
with the automatic numbering.
\eqnum works with both single-line and multiline equations.
You could, if you wished, do all the numbering in a paper
manually with \eqnum.
Enclosing single-line and multiline equations in begin{mathletters}
and end{mathletters} will produce
a set of equations that are ``numbered'' with letters, as shown
in Eqs. (8a) and (8b) below:
If you wish to set a multiline equation without any line numbers,
you can use the \verb+\begin{eqnarray*}+,
\verb+\end{eqnarray*}+ format:
\begin{eqnarray*}
\sum \vert M^{\rm viol}_g \vert ^2&=&g^{2n-4}_S(Q^2)~N^{n-2}
(N^2-1)\\
& &\times \left( \sum_{i<j}\right)
\left( \sum_{\rm perm}
{1 \over S_{12}S_{23}S_{n1}}\right)
{1 \over S_{12}}~.
\end{eqnarray*}
To obtain numbers not normally produced by the automatic numbering,
use the \verb+\eqnum{#1}+ command, where \verb+#1+ is the desired
equation number. For example, to get an equation number of
(\ref{eq:mynum}),
\begin{equation}
g^+g^+ \rightarrow g^+g^+g^+g^+ \dots ~,~~q^+q^+\rightarrow
q^+g^+g^+ \dots ~. \eqnum{2.7$'$}\label{eq:mynum}
\end{equation}
{\it A few notes on} \verb=\eqnum=.
The \verb+\eqnum+ must come before the \verb+\label+, if any.
The numbering set with \verb+\eqnum+ is {\it transparent} to the
automatic numbering in REV\TeX; therefore
you must know the number ahead of time and {\it must\/} make
sure that the number set with \verb+\eqnum+ stays in step
with the automatic numbering.
\verb+\eqnum+ works with both single-line and multiline equations.
You could, if you wished, do all the numbering in a paper
manually with \verb+\eqnum+.
Enclosing single-line and multiline equations in \btt{begin\{mathletters\}}
and \btt{end\{mathletters\}} will produce
a set of equations that are ``numbered'' with letters, as shown
in Eqs.\ (\ref{mlett:1}) and (\ref{mlett:2}) below:
\begin{mathletters}
\begin{equation}
\left\{abc123456abcdef\alpha\beta\gamma\delta%
1234556\alpha\beta{1\sum^{a}_{b}\over A^2}\right\},\label{mlett:1}
\end{equation}
\begin{eqnarray}
{\cal M}=&&ig_Z^2(4E_1E_2)^{1/2}(l_i^2)^{-1}
(g_{\sigma_2}^e)^2\chi_{-\sigma_2}(p_2)\nonumber\\
&&\times
[\epsilon_i]_{\sigma_1}\chi_{\sigma_1}(p_1).\label{mlett:2}
\end{eqnarray}
\end{mathletters}