Minimal working example:

```
\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\[ {A^\mu}_\nu \]
\[ {\bar{A}^\mu}_\nu \]
\end{document}
```

The result is.

Why is the placement of upper and lower indices in the second one wrong?

Skip to content
# [Tex/LaTex] Weird relative positioning of superscript and subscript with \dot, \bar

math-modesubscriptssuperscripts

Minimal working example:

```
\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\[ {A^\mu}_\nu \]
\[ {\bar{A}^\mu}_\nu \]
\end{document}
```

The result is.

Why is the placement of upper and lower indices in the second one wrong?

## Best Answer

From the TeXbook, p. 290:

So in the first example

the <math field> is

`A^\mu`

which has a superscript, so the braces are not removed. In the second example,we are in the other situation, because

`\bar{A}`

is an Acc atom. So the braces are removed and ineffective.Why did Knuth choose to do this? I don't really know, but the main reason could be the connected to making double accents. In a case such as

one would like to put the second bar over

`\bar{A}`

, rather than over the whole subformulas. Actually the Plain TeX macros don't easily allow for making double math accents, problem which is solved by`amsmath`

.