# [texhax] parenthesis problem in LaTeX

Tom Schneider toms at ncifcrf.gov
Sat Jan 17 21:36:37 CET 2009

Reinhard:

>
>   \left( a+b \middle) \times \middle( \frac{a}{b} \right)
>
>
> As always: Whenever you've found out how things work, then you also
> understand the manual. :)

Yes, I see how that works now.

> But there is a hint in the manual though it can easily be overlooked:
> \middle<delimiter>.  This explains the error message you got
> (! Missing delimiter).

Of course the trouble with a vague message like that doesn't say what
to do ...  In this case the message was
fails with '! Missing delimiter (. inserted).
which is quite confusing because the '(' and the ')' could be read as
part of the message or as the symbols to be inserted.  But it looks like
maybe one needs a period somehow ...

> BTW, here is a single-line example file for plain TeX:
>
> $$\left( a+b \middle) \times \middle( a \over b \right)$$ \bye
>
> Please note that it doesn't work with tex.  You have to use etex,
> pdftex, pdfetex, ... instead.  I didn't try, but I'm very sure that
> you can use \middle in Context, eplain, texinfo,... too.  In short: It
> works on any machine which prints "entering extended mode" to screen.

My LaTeX is telling me it is "entering extended mode".

Thanks to everyone; my talk went well!

Tom

Dr. Thomas D. Schneider
National Institutes of Health
National Cancer Institute
Center for Cancer Research Nanobiology Program
Molecular Information Theory Group
Frederick, Maryland  21702-1201
toms at ncifcrf.gov
permanent email: toms at alum.mit.edu
http://www.ccrnp.ncifcrf.gov/~toms/