cross-referencinglyxtable of contents
Is there any way to cross-reference to sections/subsections via their title? I find myself writing "Please see section 4 for more details", and it gets annoying very soon, especially when I have to change the numbers repeatedly.
I am using lyx, so it would be nice if there's some way of automating some of the steps.
Add the following code to the preamble settings of your LyX document:
\usepackage{chngcntr}
In the document body, add the following "Evil Red Text" (LaTeX code) immediately after \appendix to effect the desired change for an environment called thm:
\counterwithin{thm}{section}
% \renewcommand{\thethm}{\thesection\arabic{thm}}% optional
You'll have to check your preamble for the existing theorem-like environments and their names (AFAIK, this depends on the loaded LyX modules) and apply the above code for every environment.
Here's a compilable example:
\documentclass{article}
\newtheorem{thm}{Theorem}
\usepackage{chngcntr}
\begin{document}
\section{First}
\begin{thm}
A theorem.
\end{thm}
\section{Second}
\begin{thm}
Another theorem.
\end{thm}
\appendix
\counterwithin{thm}{section}
% \renewcommand{\thethm}{\thesection\arabic{thm}}% optional
\section{App-First}
\begin{thm}
An appendix theorem.
\end{thm}
\section{App-Second}
\begin{thm}
Another appendix theorem.
\end{thm}
\end{document}
Let our LyX document be called mypaper.lyx. Under “Document > Settings...” we add two branches: “fulltext” and “shorttext” both with filename suffix set to “Yes”. (As mentioned, “branches” are used in LyX to manage several different variants of one document.)
When only the branch “fulltext” is activated we call this the full version of the document; when only the branch “shorttext” is activated we call this the short version of the document.
The branch “fulltext” shall contain all the details, e.g., a float table (with the label “tab:1”). Such details are placed inside a “branch box”, which is created by “Insert > Branch > 1. fulltext”. Furthermore, the branch “shorttext” will only contain a cross-reference “Table [Ref: tab:1]” to that table in the long version.
So far we got the following LyX document with two branches:
How to generate the short version mypaper-shorttext.pdf and the full version mypaper-fulltext.pdf?
First, we activate the “fulltext” branch only and compile the full version (as PDF), to which we want to refer in the short version. The file name of the output will be mypaper-fulltext.pdf as you may see in the PDF viewer.
Then, we add two lines to the LaTeX Preamble of mypaper.lyx.
\usepackage{xr}
\externaldocument{mypaper-fulltext}
where mypaper-fulltext is the filename without extension of the just created output.
Finally, we activate the “shorttext” branch only and compile the short version.
The outputs are:
Warnings
Background – how does this work in LyX?
For compiling a document, LyX exports a document to a LaTeX file in a temporary directory and runs the program “pdflatex” (or similar) to create the output. Luckily LyX uses the same temporary directory when compiling the short version and the full version. Hence, the files mypaper-shorttext.tex, mypaper-shorttext.aux, mypaper-fulltext.tex, mypaper-fulltext.aux are in the same directory. By using \externaldocument{mypaper-fulltext} LaTeX will find the necessary files like mypaper-fulltext.aux. After a new start of LyX, the temporary directory is empty again. Hence, the full version needs to be compile first to create the files mypaper-fulltext.tex, mypaper-fulltext.aux.
Extensibility: If the “shorttext” branch contains labels that are referred by the long version then we need to add \externaldocument{mypaper-shorttext} to the LaTeX Preamble, too, and keep the short version compiled (updated), too. More complex scenarios with several branches are possible.
Best Answer
Use
\labeland\ref....
More details can be found in the Not So Short Introduction to LaTeX2e, which is worth reading.
The cleveref package can save you some typing by automatically preceding the reference with section, theorem, equation, etc. as appropriate.