# [luatex] How to get a \mid binary relation that grows in LuaTeX

David Carlisle d.p.carlisle at gmail.com
Wed Nov 15 15:53:52 CET 2017

On 15 November 2017 at 14:16, Hans Hagen <pragma at wxs.nl> wrote:

Hans, thanks for the reply

> (3) the good news is that you can do this:
>
>     \left( a \Umiddle class 5 | b \right)
>
> Hans
>

Ooh that is news:-) (the luatex manual doesn't seem to mention a
possibility of class here)
but why 5 (closing)? I'd have expected to specify 3 (relation) to get
symmetric spacing but that gives thinmuspace not thickmuspace (at
least with luatex 1.04 as distributed with texlive)

David