Exporting math code containing a cases environment to LaTeX

Exporting math code containing a cases environment to LaTeX

[Francesco Turco]

Why the following piece of Org Mode document doesn't display correctly
when exported to a PDF document via LaTeX?

  \[n!=
  \begin{cases}
    1 & n=0 \\
    n(n-1)! & n\ge 1 \\
  \end{cases}
  \]

It is displayed at the left instead of center of the document.
Moreover the \[ and \] symbols are not removed in the final document.

I can fix the problem by replacing \[ and \] with \begin{displaymath}
end \end{displaymath} respectively:

  \begin{displaymath}  
  n!=
  \begin{cases}
    1 & n=0 \\
    n(n-1)! & n\ge 1 \\
  \end{cases}
  \end{displaymath}

Is this the best way to fix the problem? Am I missing a better solution?

Re: Exporting math code containing a cases environment to LaTeX

[Eric S Fraga]

On Saturday, 12 Mar 2016 at 18:49, Francesco Turco wrote:
> I can fix the problem by replacing \[ and \] with \begin{displaymath}
> end \end{displaymath} respectively:
>
>   \begin{displaymath}  
>   n!=
>   \begin{cases}
>     1 & n=0 \\
>     n(n-1)! & n\ge 1 \\
>   \end{cases}
>   \end{displaymath}
>
> Is this the best way to fix the problem? Am I missing a better solution?

The \[ ... \] construct is only valid, in org, if on a single
line.  Your solution is perfectly valid although, in practice, I would
use equation* instead of displaymath.

Alternatively, you can enclose it all in a export block, as in

#+begin_export latex
\[
...
\]
#+end_export

-- 
: Eric S Fraga (0xFFFCF67D), Emacs 25.0.91.1, Org release_8.3.4-626-gb62d55

Re: Exporting math code containing a cases environment to LaTeX

[Francesco Turco]

On Sat, Mar 12, 2016, at 19:16, Eric S Fraga wrote:
> Alternatively, you can enclose it all in a export block, as in
> 
> #+begin_export latex
> \[
> ...
> \]
> #+end_export

The following code doesn't work:

#+begin_export latex
\[
n!=
\begin{cases}
  1 & n=0 \\
  n(n-1)! & n\ge 1 \\
\end{cases}
\]
#+end_export

Because of the following error message:

> ! LaTeX Error: Environment export undefined.

But I can use #+begin_latex and #+end_latex instead.

I read the former syntax is new and will be released with Org Mode 9.0.
Is that true?

See https://www.mail-archive.com/emacs-orgmode@gnu.org/msg102960.html

Re: Exporting math code containing a cases environment to LaTeX

[Eric S Fraga]

On Saturday, 12 Mar 2016 at 19:33, Francesco Turco wrote:

[...]

> But I can use #+begin_latex and #+end_latex instead.
>
> I read the former syntax is new and will be released with Org Mode 9.0.
> Is that true?

Yes, indeed.  I forgot to ask what version of org you were using!

I'm glad the old format works for you.

Re: Exporting math code containing a cases environment to LaTeX

[Francesco Turco]

On Sun, Mar 13, 2016, at 09:13, Eric S Fraga wrote:
> Yes, indeed.  I forgot to ask what version of org you were using!
> 
> I'm glad the old format works for you.

I forgot to thank you for the help! :)