Make Theorem header a link to proof environment

Question

I have a similar question to (Making a theorem into a link) but I was not able to adjust it accordingly.

I have some proofs in an appendix and I would like to have a theorem environment where the header links to the proof. Something like,

\begin{linkthm}{\ref{proof:ex_thm}} \label{ex_thm}

\end{linkthm}

Thank you!

Answer 1

I suggest you make use of the \hypertarget/\hyperlink mechanism provided by the hyperref package. Both commands take two arguments; the first argument of a linked pair of such commands should be the same.

In the following example, clicking on the word "Pythagoras" in the theorem's header while in the pdf file will take the reader to the associated proof.

---

\documentclass{article}

\usepackage{amsthm} % or '\usepackage{ntheorem}'
\usepackage[colorlinks,allcolors=blue]{hyperref}
\usepackage[nameinlink,noabbrev]{cleveref} % optional
\newtheorem{theorem}{Theorem}

\begin{document}

\section{Main results}

\begin{theorem}[\hyperlink{proof:pyth}{Pythagoras}] \label{thm:pyth}
Let $a$, $b$, and $c$ denote the lengths of the sides 
of a \emph{right triangle}, i.e., of a triangle with 
one angle equal to $90^\circ$. Without loss of generality 
assume that $a\le b<c$. Then $a^2+b^2=c^2$.
\end{theorem}

\clearpage

\appendix

\section{Proofs of all theorems}

\begin{proof}[\hypertarget{proof:pyth}{Proof of \Cref{thm:pyth}}]
\dots
\end{proof}

\end{document}

Answer 2

You can try and fix the position of the anchor, because raiselinks (which should work) doesn't seem to suffice.

\documentclass{article}

\usepackage{amsthm} % or '\usepackage{ntheorem}'
\usepackage[raiselinks,colorlinks,allcolors=blue]{hyperref}
\usepackage[nameinlink,noabbrev]{cleveref} % optional

\usepackage{lipsum}


\newtheorem{linkthminner}{\hyperlink{\linkthmlabel}{Theorem}}
\crefname{linkthminner}{theorem}{theorems}
\Crefname{linkthminner}{Theorem}{Theorems}

\NewDocumentEnvironment{linkthm}{mo}{%
  % #1 is the label, #2 the possible attribution
  \renewcommand{\linkthmlabel}{#1}%
  \IfNoValueTF{#2}{\linkthminner}{\linkthminner[#2]}\label{#1}%
}{\endlinkthminner}
\newcommand{\linkthmlabel}{}% initialize
\newenvironment{linkproof}[1]{%
  \proof[\hypertarget{#1}{\strut\proofname\ of \cref{#1}}.]%
}{\endproof}

\begin{document}

\section{Main results}

\begin{linkthm}{thm:a}
This is a theorem statement. \lipsum[2][1-5]
\end{linkthm}

\begin{linkthm}{thm:b}[Someone]
This is a theorem statement. \lipsum[2][1-5]
\end{linkthm}

\lipsum[1-10]

\appendix

\section{Proofs of all theorems}

\begin{linkproof}{thm:a}
\lipsum[1-2]
\end{linkproof}

\begin{linkproof}{thm:b}
\lipsum[1-2]
\end{linkproof}

\end{document}