# Commath

Commath.sty contains a variety of useful environments/commands, including \eval (“evaluate at”), \dfrac (\displaystyle\frac), \od (ordinary differential equations), etc. I do not personally use \dfrac or \od though: these commands display the fraction very small; I would renewcommand \dfrac as:

\renewcommand{\dfrac}{\displaystyle\frac},

You could also redefine \od but is more tricky because it has two arguments.

#
Line numbers disappear when using lineno.sty and align env.

lineno.sty provides line numbers on PDF. However, on paragraphs with equation(s), line numbers may disappear. To prevent this, issue:

\newcommand*\patchAmsMathEnvironmentForLineno[1]{% \expandafter\let\csname old#1\expandafter\endcsname\csname #1\endcsname \expandafter\let\csname oldend#1\expandafter\endcsname\csname end#1\endcsname \renewenvironment{#1}% {\linenomath\csname old#1\endcsname}% {\csname oldend#1\endcsname\endlinenomath}}% \newcommand*\patchBothAmsMathEnvironmentsForLineno[1]{% \patchAmsMathEnvironmentForLineno{#1}% \patchAmsMathEnvironmentForLineno{#1*}}% \AtBeginDocument{% \patchBothAmsMathEnvironmentsForLineno{equation}% \patchBothAmsMathEnvironmentsForLineno{align}% \patchBothAmsMathEnvironmentsForLineno{flalign}% \patchBothAmsMathEnvironmentsForLineno{alignat}% \patchBothAmsMathEnvironmentsForLineno{gather}% \patchBothAmsMathEnvironmentsForLineno{multline}% }

It might be more useful to create your own .sty file to automatically solve this problem.

# How to track changes

One possible difficulty in writing a co-authored paper is how to highlight changes. There are basically three ways:

- Use texdiff (perl-based?)
- Use changes.sty (included in TeXLive)
- Use trackchanges.sty (http://trackchanges.sourceforge.net/)

I mainly use **trackchanges.sty** (by locating its symbolic link in TeXLive). I found some pros and cons for each; texdiff is the easiest but readability is low, I thought (no waving underline needed to me!!). Changes.sty was not comfortable to me (I forgot the reason but I tried at one point). TrackChanges.sty was useful, with a potential incompatibility with \cite command or {equation} environment. It does not go without adding\protect command before \cite (or any other commands of .bib citation) and \begin{equation}.