# [Tex/LaTex] Using aligned and align without amsmath

alignamsmath

I am currently working on a proceedings paper, and have realised after finishing it that only specific packages are permitted – one of which is not amsmath. As a result, many of the nice equations that I have written can now no longer be built. To save me switching back to \begin{cases} \end{cases} and giving up, I thought I would try asking on here to see if anyone could provide me with a solution?

I cannot define add any new commands before \begin{document}, so everything must be done after that point. I thought about trying to grab the relevant components from the style file, but to be perfectly honest I am not a TeX-wizard and have no idea whether this would even work.Could anyone provide me with a work-around, so that I can still use align and aligned, but by doing so after \begin{document}?

If it helps, the packages I am permitted to use are:

\usepackage{mathptmx}
\usepackage{helvet}
\usepackage{courier}
\usepackage{type1cm}
\usepackage{graphicx}
\usepackage[bottom]{footmisc}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsbsy}
\usepackage{amscd}
\usepackage{amstext}
\usepackage{dsfont}
\usepackage[english]{babel}
\usepackage{color}
\usepackage{graphics}
\usepackage{epsfig}
\usepackage{subfigure}
\usepackage{wrapfig}
\usepackage{psfrag}
\usepackage{color}
\usepackage{url}
\usepackage{verbatim}
\usepackage{algorithm}
\usepackage{algorithmic}


Edit: An MWE is as follows:

\documentclass{svmult}
\usepackage{mathptmx}
\usepackage{helvet}
\usepackage{courier}
\usepackage{type1cm}

\usepackage{graphicx}

\usepackage[bottom]{footmisc}

\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsbsy}
\usepackage{amscd}
\usepackage{amstext}
\usepackage{dsfont}
\usepackage[english]{babel}
\usepackage{color}
\usepackage{graphics}
\usepackage{epsfig}
\usepackage{subfigure}
\usepackage{wrapfig}
\usepackage{psfrag}
\usepackage{color}
\usepackage{url}
\usepackage{verbatim}
\usepackage{algorithm}
\usepackage{algorithmic}

\begin{document}

\label{InitSystemNL} \left\{ \begin{aligned} \mathcal{R} \colon= -\Delta u &= f \quad & &\text{in} \,\, \Omega \\ u &= 0 \quad & &\text{on} \,\, \partial\Omega, \end{aligned} \right.

\end{document}


To avoid needing to edit the existing doc you can defined a poor man's aligned as follows (but first try to get the rules changed)

\documentclass{article}
\usepackage{mathptmx}
\usepackage{helvet}
\usepackage{courier}
\usepackage{type1cm}

\usepackage{graphicx}

\usepackage[bottom]{footmisc}

\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsbsy}
\usepackage{amscd}
\usepackage{amstext}
\usepackage{dsfont}
\usepackage[english]{babel}
\usepackage{color}
\usepackage{graphics}
\usepackage{epsfig}
\usepackage{subfigure}
\usepackage{wrapfig}
\usepackage{psfrag}
\usepackage{color}
\usepackage{url}
\usepackage{verbatim}
\usepackage{algorithm}
\usepackage{algorithmic}

\begin{document}
\def\aligned{\vcenter\bgroup\let\\\cr
\halign\bgroup&\hfil${}##{}$&${}##{}$\hfil\cr}
\def\endaligned{\crcr\egroup\egroup}

\label{InitSystemNL} \left\{ \begin{aligned} \mathcal{R} \colon= -\Delta u &= f \quad & &\text{in} \,\, \Omega \\ u &= 0 \quad & &\text{on} \,\, \partial\Omega, \end{aligned} \right.

\end{document}