Alternative theorem numbering separator

I'm using amsthm and I want to have this numbering format for my theorems: Chapter-Section-Theorem

The main difference with the default version is the use of "-" instead of "." .

Can I do this by defining a new theoremstyle?

• Almost certainly possible, but are you using any packages? If so, which ones? Hence the common request for a minimal working example – cmhughes Apr 30 '16 at 22:19
• @cmhughes, I'm using amsthm. – NEO Apr 30 '16 at 22:23
• I solved it myself: \newtheorem{theorem}{Theorem}[section] \renewcommand{\thetheorem}{\thesection-\arabic{theorem}} Anybody knows any better solution? Perhaps defining this in my customized class? – NEO Apr 30 '16 at 22:42
• This method will give you theorem numbering of the form n.m-num, not n-m-num. – Mico Apr 30 '16 at 22:47
• Yes, you are right. In my code I have previously defined thesection to reflect n-m. – NEO May 1 '16 at 8:48

Something like this?

\documentclass{report} % document class that features 'chapter' sectioning level
\usepackage{amsthm}
\theoremstyle{plain}
\newtheorem{thm}{Theorem}[section]
\renewcommand\thethm{\thechapter-\arabic{section}-\arabic{thm}}
\begin{document}

\setcounter{chapter}{2}
\setcounter{section}{3}
\begin{thm} aaa \label{thm:aaa} \end{thm}

A cross-reference to Theorem \ref{thm:aaa}.

\end{document}