Question: I want to type something like this page <http://caml.inria.fr/pub/docs/manual-ocaml/expr.html>. So I need to use `\begin{align*}` and `\end{align*}` which displays its contents math mode. Therefore italic font is needed. But when I type directly "value-path" for instance, its letters look very loose.

Does anyone know how to make its letters tighter?

Answer: 
For "multiletter identifiers", use `\mathit{expr}`.
```
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{bera}
\usepackage{array}
\begin{document}
\begin{center}
\tabcolsep=1.4pt
\tabular[t]{@{} >{\itshape}l c >{\itshape}l @{}}
expr & ::= & value-path\\  
     &  |  & constant  \\
     &  |  & ( expr )  \\
\endtabular
\end{center}

\end{document}

```

![enter image description here](https://i.stack.imgur.com/gVPJ3.png)