On 15 November 2017 at 14:16, Hans Hagen <pra...@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
