General ⇒ Shortning commands such as \begin{gathered}

[railfan1975]

I use some commands, such as \begin{gathered} a lot. I would like to replace them with shorter commands. I tried using \newcommand{\bg}{\begin{gathered}}, but it gave me an error.

Is there any way of doing this short of creating a package?

Thanks!

JT

[gmedina]

Many of the commands and environments provided by the amsmath package are fragile so shortcuts as the one you defined are a recipe for disaster, as you have already experienced.

You can define a synonym for those environments using something like

Code: Select all

\documentclass{article}
\usepackage{amsmath}

\newenvironment{gatd}{\gathered}{\endgathered}

\begin{document}

\begin{equation}
  \begin{gatd}
    (a+b)(a-b)=a^2-b^2\\
    (a+b)(a+b)=a^2+2ab+b^2
  \end{gatd}
  \begin{gatd}
    (a-b)(a-b)=a^2-2ab+b^2\\
    (a-b)(a+b)=(a+b)(a-b)
  \end{gatd}
\end{equation}

\end{document}

[Juanjo]

Try

Code: Select all

\let\bg\gathered
\let\eg\endgathered

So you can write something like

Code: Select all

\[
\bg
 a+b+c=d+e \\
 f+g+h=i
\eg
\]

Anyway, I think doing that is a bad practice, since the internal checks for environments that remain open are then disabled. Suppose you forget \eg. Compile and look at the error. Now, replace \bg by \begin{gathered} and compile. Which error is easier to debug?

[balf]

The best solution, I think, is a good editor that lets you have shorthands to typeset in a stroke the whole environment, then have the cursor at the right place. It is important that the source code remains readable .

B.A.

[Stefan Kottwitz]

Hi JT,

short workaround:

Code: Select all

\def\bg#1\eg{\gathered#1\endgathered}

Or:

Code: Select all

\newcommand\gath[1]{\gathered#1\endgathered}

You can read something about the problem with abbreviating amsmath environments in the amsmath technical notes.

Stefan