# How to indent the text within a theorem?

I would like the text of a long theorem to be indented, so that the text of the second line starts exactly below the text of the first line (and not below the word "Theorem") like this:

Theorem 1: This is a long thoerem where I would like the text in the second
line to be indented.

Here is a small example, where the text is unfortunately not indented.

\documentclass{article}

\newtheorem{Theorem}{Theorem}

\begin{document}

\begin{Theorem}
This is a long thoerem where I would like the text in the second line to be indented.
\end{Theorem}

\end{document}


Does anyone have an idea how to solve this?

Update: Based on the answer of Werner and the corresponding comments below, I would like to extend the example as follows, where I also create a table of theorems as well as references to the theorems in the footer, which currently does not work with the solution provided by Werner:

\documentclass[8pt]{extbook}

\usepackage{amsthm}
\usepackage{enumitem}
\usepackage{fancyhdr}
\usepackage{titletoc}
\usepackage{tocloft}

\theoremstyle{TheoremStyle}
\newtheorem{Theorem}{Theorem}

\makeatletter

\newcommand\TableofTheorems{\chapter*{Table of Theorems}\@starttoc{ToT}}

\begin{document}

\TableofTheorems
\newpage

\pagestyle{fancy}

\section*{Chapter 1}

\begin{Theorem}[This is a long thoerem where I would like the text in the second line to be indented.]
This is a long thoerem where I would like the text in the second line to be indented.
\end{Theorem}

\newpage

\begin{Theorem}[This is another theorem.]
This is another theorem.
\end{Theorem}

\newpage

\begin{Theorem}[This is the third Theorem]
This is another theorem.
\end{Theorem}

\end{document}


Theorems are actually lists. You can use enumitem to format a list that is represented in the way you want, while tocloft aids in setting up content for the List of Theorems:

\documentclass{article}

\newtheorem{Theorem}{Theorem}% Original Theorem definition

\usepackage{enumitem,tocloft}

\newenvironment{MyTheorem}[1][]{%
\def\theoremtocarg{#1}% Capture optional argument
\begin{enumerate}[
series=theoremlist, % Maintain unique counter
resume=theoremlist, % Continue from previous counter
align=left,
leftmargin=*,
label={\bfseries Theorem \arabic*},
ref=\arabic*
]
\item \itshape%
}{%
\end{enumerate}
}

\newlistof[section]{theorem}{tot}{List of Theorems}% Define List of Theorems
\renewcommand{\cfttottitlefont}{\Large\bfseries}% Default for \section

\begin{document}

\listoftheorem

\section{First section}

\begin{Theorem}
This is a long theorem where I would like the text in the second line to be indented.
\end{Theorem}

\begin{MyTheorem}[First theorem]
This is a long theorem where I would like the text in the second line to be indented.
\end{MyTheorem}

\begin{Theorem}
This is a long theorem where I would like the text in the second line to be indented.
\end{Theorem}

\begin{MyTheorem}[Second theorem]
This is a long theorem where I would like the text in the second line to be indented.
\end{MyTheorem}

\end{document}

• The indenting works fine, but I get two other problems: – Jack Sep 13 at 19:45
• @Jack: ...and they are? – Werner Sep 13 at 19:49
• 1) I had created the following theoremstyle in order to add them to a table of theorems (ToT) - how can I do the exact same thing for such an environment: \newtheoremstyle{TheoremStyle}{3pt}{3pt}{\bfseries}{}{\bfseries}{}{.5em}{\thmname{#1}\thmnumber{ #2} \addcontentsline{ToT}{section}{#1~\protect\numberline{#2}{#3}}} \theoremstyle{TheoremStyle} 2) I referenced to the Theorems using \thetheorem (for example to write the number of the Theorem in the footer.) Is there a similar command for the Environment as well? – Jack Sep 13 at 19:53
• @Jack: Can you supply a more complete, minimal example that replicates your current setup? What package do you use to employ \newtheoremstyle? You should really be up front about what you're using. – Werner Sep 13 at 19:57
• See update above – Jack Sep 13 at 21:38