How suppress number of numbered theorem?

Question

Is there a way, with amsthm and thmtools (possibly other packages, too) to have LaTeX keep track of the numbers of a particular kind of theorem, yet not have the numbers actually appear in the printed text?

For example:

\documentclass{article}

\usepackage{amsthm}
\usepackage{thmtools}

\declaretheoremstyle[numbered=yes]{probs}
\declaretheorem[name=PROBLEMS,style=probs,numberwithin=section]{problems} 

\begin{document}

\section{First section}

\begin{problems}
Blah-blah
\end{problems}

\end{document}

The output I want should be:

Note that the answer is not simply to use numbered=no (or, without thmtools, a \newtheorem* declaration) — because I still want to reference the theorem's number (and not a name), e.g., for use with \hyperref.

[The issue is related to my question How use cleveref to get theorem-like name and list item number?

Answer 1

I don't recommend such a style, but it is possible to trick preheadhook to let \theproblems do nothing and enable it later on again with postheadhook, such that the label option (or the \label command) will use the non-empty \theproblems anyway.

The enumeration reference can be changed however with an easy enumitem list specialized for problems:

\documentclass{article}

\usepackage{amsthm}
\usepackage{thmtools}
\usepackage{enumitem}
\usepackage{hyperref}

\declaretheoremstyle[numbered=yes]{probs}
\declaretheorem[name=PROBLEMS,style=probs,numberwithin=section,preheadhook={\let\theproblems\relax},postheadhook={\newcommand{\theproblems}{\thesection.\arabic{problems}}\leavevmode}]{problems} 

\newlist{probenum}{enumerate}{1}

\setlist[probenum,1]{label={\arabic*)},ref={Problem \thesection(\arabic*)}}


\begin{document}


\section{First section}

\begin{problems}
\begin{probenum}
  \item foo \label{foo}
  \item bar \label{bar}
\end{probenum}
\end{problems}


\section{other}

\begin{problems}
\begin{probenum}
  \item foo \label{fooother}
  \item bar \label{barother}
\end{probenum}
\end{problems}

In \ref{fooother}, \ref{bar} or in \ref{foo} it is shown that

\end{document}