TeX capacity exceeded
add tag
निरंजन 
```
\documentclass{article}
\renewcommand{\&}{\textbf{\&}}

\begin{document}
\&
\end{document}
```

Pretty basic question. I have looked for [this](https://tex.stackexchange.com/questions/24247/tex-capacity-exceeded-sorry-input-stack-size-5000) on TeX.SE, but it doesn't capture my problem well. Please explain why I am getting this error. Also how to change all the `\&`s to bold ones in the preamble itself?
Top Answer
samcarter 
The problem is that inside your command definition you use the redefined command - this creates an infinite loop. 

A simple solution is to store the old definition of the command like this:

```
\documentclass{article}

\let\oldampersand\&
\renewcommand{\&}{\textbf{\oldampersand}}

\begin{document}
ge \& erj
\end{document}
```
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