# Itemizing theorem body

Using package amsthm, the desired theorem style achieved,

\documentclass{book}
\usepackage{amsthm}

\newtheoremstyle{mystyle}{}{}{}{}{\bf}{}{\newline}{}
\theoremstyle{mystyle}
\newtheorem*{mythm}{Theorem}

\begin{document}
\begin{mythm}
This is a normal body text.
\end{mythm}
\end{document}


But itemizing the body makes trouble,

\documentclass{book}
\usepackage{amsthm}

\newtheoremstyle{mystyle}{}{}{}{}{\bf}{}{\newline}{}
\theoremstyle{mystyle}
\newtheorem*{mythm}{Theorem}

\begin{document}
\begin{mythm}
\begin{itemize}
\item This an itemized body text.
\item This an itemized body text.
\end{itemize}
\end{mythm}
\end{document}


As the last output shows, first item has jumped to the head line.

How can I bring it back to the body?

• potential duplicate: Enumerate alignment problem in theorem environment – barbara beeton Apr 30 '16 at 12:58
• Actually this is not a duplicate. I do not want to align items with what is on head line. – Shaqpad Apr 30 '16 at 13:01
• Use \leavevmode before \begin{itemize} – user31729 Apr 30 '16 at 13:05
• @Shaqpad -- the use of \leavevmode is exactly what that answer recommends, as christian has repeated. items are not aligned with the head line, but treated as a "usual" list. i'll add an example to the cited answer to make this clear. – barbara beeton Apr 30 '16 at 13:42
• @Christian Hupfer: leavevmode is not enough, as there will be a spurious vertical space. – Bernard Apr 30 '16 at 15:00

Here is a solution with enumitem. One can define a thmitemise clone, which incorporates by default the given setup, to avoid having to type it each time it is used:

\documentclass{book}
\usepackage{amsthm} \newtheoremstyle{mystyle}{}{}{}{}{\bf}{}{\newline}{}
\theoremstyle{mystyle}
\newtheorem*{mythm}{Theorem}
\usepackage{enumitem, showframe}

\begin{document}

\begin{mythm}
\begin{itemize}[wide=0.5em, leftmargin =*, nosep, before = \leavevmode\vspace{-\baselineskip}]
\item This an itemized body text.
\item This an itemized body text.
\end{itemize}
\end{mythm}
\end{document}


here is a mechanism for removing the extra space between the theorem head and the list. i don't really like it, but it will provide necessary information to make this a feature of the ams theorem facility when that is overhauled. (latex doesn't make things like this easy.)

\documentclass{amsart}
\newtheorem{thm}{Theorem}[section]

\begin{document}
\begin{thm}
\leavevmode
\makeatletter
\@nobreaktrue
\makeatother
\begin{enumerate}
\item Item 1
\item Item 2
\item Item 3
\end{enumerate}
\end{thm}
\end{document}


An even easier solution may be this:

\usepackage[inline]{enumitem}
\begin{mythm}
\begin{enumerate}[label=(\arabic*)]
\item[]
\item state 1
\item state 2
\end{enumerate}
\end{mythm}


Possibly the easiest solution is hfill

\begin{theorem}
\hfill
\begin{enumerate}
\item Item 1
\item Item 2
\item Item 3
\end{enumerate}
\end{theorem}