# How to use case 1, case 2 in a proof (IEEE confs)

I want to show:

proof:
Case 1: .....
Case 2: .....

in a proof. The following is my rough codes:

\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}

\begin{proof}
\newenvironment{case}

\begin{case}
\item[title 1] XXXX
\end{case}

\begin{case}
\item[title 2] XXXX
\end{case}

\end{proof}
\end{document}


However, Latex shows \begin (proof) on input ended by \end (case)

How to show what I want to show?

The following is what I find; however, I cannot still finish it. Case numbering within proof

• \newenvironment{}{}{} defines a new environment but you haven't given it a definition. See my answer here for information about writing your own macros (commands and environments). – cfr Jun 18 '15 at 23:39

## 1 Answer

Something like this?

\documentclass[12pt]{article}
\usepackage{mathtools,amsthm}
\newtheoremstyle{case}{}{}{}{}{}{:}{ }{}
\theoremstyle{case}
\newtheorem{case}{Case}
\begin{document}

\begin{proof}
\begin{case}
something
\end{case}
\begin{case}
case
\end{case}
\end{proof}

\end{document}


• This one does not refresh the counter after the proof environment ends. So for the next proof environment, it starts with Case 3. – Subhajit Paul Oct 28 '18 at 16:37
• \usepackage{chngcntr} and \counterwithin*{case}{lemma} etc., should fix that. – Freddie Manners Apr 18 at 21:52