# How to force a linebreak in itemization?

I have a proposition which consists of two itemized bullets. I want both to be displayed in an offset way, but the first one keeps getting displayed as a continuation of the Proposition in bold.

How to get what I want?

This is my code.

\documentclass[12pt]{amsart}
\usepackage{amsthm}
\usepackage{amssymb}
\usepackage{latexsym}
\usepackage{url}
\title{whatever}
\newtheorem{thm}{Theorem}[section]
\newtheorem{prop}[thm]{Proposition}
\begin{document}
\begin{prop}
This is the usual display.
\end{prop}
\begin{prop}
\label{prop:twocases}
\begin{itemize}
\mbox{} \item If $b_{1} \leq \sqrt{x}$, then: $\epsilon_{i}=\epsilon_{i}^{+}, i \in \{1,2,3\}.$
\item If $b_{1} > \sqrt{x}$, then either $\epsilon_{i}=\epsilon_{i}^{+}, i \in \{1,2,3\}$ or $\epsilon_{i}=\epsilon_{i}^{-}, i \in \{1,2,3\}.$
\end{itemize}
\end{prop}
\end{document}

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How is the prop environment defined? If it's defined with the ntheorem package, you could insert the instruction \theoremstyle{break} prior to prop getting set up; this will force a line break after Proposition <num>. –  Mico Jul 10 '12 at 13:03
But I don't want a linebreak every time. I guess I could define two separate prop environments, but it's rather awkward. Thanks anyway. Other ideas? –  Felix Goldberg Jul 10 '12 at 13:15
you can use \mbox{}\begin{itemize.... as a quick workaround –  David Carlisle Jul 10 '12 at 13:23
@FelixGoldberg moved where? Please (for any question) make a complete document that may be run that shows the problem, and all packages required to reproduce. –  David Carlisle Jul 10 '12 at 13:53
Felix, I've edited your question to include the document from your comment. You may have been able to do that yourself, but regardless, there it is. –  Mike Renfro Jul 10 '12 at 14:11

You put the \mbox{} in the wrong place:

 \mbox{}\begin{itemize}


Is where it should go.

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Thanks David, now it works like a charm! –  Felix Goldberg Jul 10 '12 at 14:29

I found that \mbox{}\begin{itemize} caused too much of a gap so I defined a new command

\newcommand{\gap}{\mbox{}\vspace{-5mm}}


to put before the \begin{itemize}. This enabled me to regulate how much space I wanted (I found this was about enough just to skip down a line).

It's a pretty crude way of doing stuff but it worked well for me since I only wanted to do it for a few of my definitions and didn't want to define a new theoremstyle as I wanted to keep the counter going for my definitions.

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Welcome to TeX.SX! –  mafp Aug 25 '13 at 23:33