[Tex/LaTex] Why is the cross reference not working and some other questions

cross-referencingsyntax

I am a TEX beginner and I am now learning how to create a reference. I am reading the book "The Not So Short Introduction to LATEX2" by Oetiker, Partl, Hyna, Schlegl; on page 42 section 2.8 Cross Reference, the code is written as

A reference to this section \label{sec:this} looks like:
"see section~\ref{sec:this} on page~\pageref{sec:this}"

And I am using CTex and WinEdt and my questions are:

I made a pdf file from the above code, but the section and page numbers are not highlighted and I cannot click on them. Why is it so?
I tried to make a reference to other pages by typing its page number like {sec:37}, but it does not work. How can I fix it?
What does the code sec actually mean? Is it arbitrary or a predefined syntax?
When I typed \label{}, a menu box named Labels (51) appeared, and there is a dropdown menus like c:ISYAC, c:UNBOUND, c:UNIFBURN,… etc… what is that? Do we have to choose from those list or can we write our own like {sec:this}?

Helps are greatly appreciated! Many many thanks!

Best Answer

The general mechanism is to set an anchor some where in your document with \label{<name>}, where <name> can be a combination of numbers, letters, : and - (to be safe). These anchors must be set explicitly by the author, thats why \ref{sec:47} doesn’t work unless it is not defined by you. After setting up an anchor you can refer to it with \ref{<name>} (giving the corresponding counter, like chapter or section or equation or … number) or \pageref{<name>} (giving the corresponding page number).

Some author use identifiers like sec:, eq:, thm: etc. to make anchor names more human readable but this is not necessary for the mechanism to work.

packages
LaTeX’s mechanism can be extended by some packages:

hyperref makes references click-able hyper links (and has some more features).
cleveref finds the right names for labels and prints \ref{anchor5} as section~5 instead of 5, for instance.
varioref compares the page numbers of anchor and reference and add text like on previous page, on page 6 etc. automatically.
nameref can print the actual title of an anchor.

MWE

\documentclass[english]{article}

% langage
\usepackage{babel}

% only for \lipsum blind text
\usepackage{lipsum}

% ref packages
\usepackage{nameref}
% folowing  must be in this order
\usepackage{varioref}
\usepackage{hyperref}
\usepackage{cleveref}

\begin{document}
\section{First section}
\lipsum[1-10]

\section{My section}\label{sec:mysection}
\lipsum[1-22]

\section{References}
\begin{itemize}
    \item \verb+\ref{sec:mysection}+: \ref{sec:mysection}
    \item \verb+\pageref{sec:mysection}+: \pageref{sec:mysection}
    \item \verb+\cref{sec:mysection}+: \cref{sec:mysection}
    \item \verb+\cpageref{sec:mysection}+: \cpageref{sec:mysection}
    \item \verb+\vref{sec:mysection}+: \vref{sec:mysection}% already combined with \cref
    \item \verb+\vpageref{sec:mysection}+: \vpageref{sec:mysection}
    \item \verb+\nameref{sec:mysection}+: \nameref{sec:mysection}
\end{itemize}
\end{document}

different references

Related Solutions

[Tex/LaTex] A better way to reference theorem-like environments

I solved this problem for myself a few years ago without knowing about the theoremref or ntheorem packages, but those in themselves do not do what you want anyway.

The problems that I had with the standard setup were the following:

You have to give each theorem type a different environment, which has both a "begin" and "end" tag containing the name of the theorem. If you want to make a change, you have to change two words not near each other.
You have to write \label every time.
You have to remember the name of the theorem type whenever you use \ref. This is the problem which theoremref also solves, though I think they do it in a slightly different way than I did.
The hyperlink produced by ref (when using hyperref) only encompasses the number and not the name ("Theorem 2", etc.), which is a small target but to change it is awkward.

I dealt with 1 and 2 by overwriting the theorem environment with one that has the syntax

\begin{theorem}{theorem type}{name of label} ... \end{theorem}

thus solving the locality problem for the theorem type and also allowing me to omit \label. For 3, I used the fncylab package to do the work that theoremref does (note that at the time, there was a bug in amsthm which makes this impossible without some work. It may be fixed now). This also takes care of 4, since now the word "Theorem" is part of the text produced by \ref, which is all wrapped in a hyperlink without my needing to do anything.

I like this solution very much. I write things like

\begin{theorem}{lem}{little lemma} This is a small lemma. \end{theorem}
It follows from \ref{little lemma} that we have
\begin{theorem*}{thm} The main result. \end{theorem*}

You can guess the effect of a theorem* environment, of course. You can see the .sty file on my website if you are interested.

Later: I just found out about the thmtools package. Man, that thing is awesome. I wish I had known about it. It does everything above (and more) and uses a keyval syntax for setting parameters, which is far better than having multiple arguments. Read p. 8 of its manual to see my hack done right. (It's not quite the same: it doesn't address point 1. However, I can imagine writing a wrapper environment taking a key "type" that would duplicate the above example.)

[Tex/LaTex] Local and global cross-references

Use \renewcommand{\thesection}{\arabic{section}} to get the numbers beside the section titles right. Changing this otherwise is difficult.

Use \renewcommand{\sectionmark}[1]{\markright{\thechapter.\thesection\ #1}} for the headers.

For the references you can use e.g. zref to set up a "fullsec" reference. But I would find it confusing. And what if you have a subsection 2.1? I would put a \label behind the chapter too and then write something like see section 1 in chapter 2.

Best Answer

Related Solutions

[Tex/LaTex] A better way to reference theorem-like environments

[Tex/LaTex] Local and global cross-references

Related Question