Theorem environment - line break after label

Question

Possible Duplicate:
ntheorem environment with indentation
Skipping line after “Proof” in proof environment

\begin{theorem}[label]
The theorem text.
\end{theorem}

I want to have automatically a line break after the label. So far I always do the following

\begin{theorem}[label]\ \\
The theorem text.
\end{theorem}

I thought of renewing the theorem environment. But I would need to do this several times since I've got a few theorem environments (lemma, proposition, corollar, etc.) and I always want a line break after the label.

It really depends on your loaded package. Please have a look at this question: http://tex.stackexchange.com/questions/5599/theorem-packages-which-to-use-which-conflict — Marco Daniel, Dec 10 '11 at 12:58
Possible duplicate of: http://tex.stackexchange.com/questions/8110/is-it-possible-to-skip-the-first-line-in-a-theorem-environment — 0 _, Apr 15 '16 at 02:24

score 31 · Accepted Answer · answered Dec 10 '11 at 13:47

31

The answer depends on the package used to declare the theorem-like structures. If you are using the ntheorem package, you can simply use the predefined break style:

\documentclass{article}
\usepackage{ntheorem}
\usepackage{lipsum}

\theoremstyle{break}
\newtheorem{theorem}{Theorem}

\begin{document}

\begin{theorem}[Some note]
\lipsum*[2]
\end{theorem}

\end{document}

enter image description here

If you are using amsthm, you will have to define your own style through the \newtheoremstyle command. Here's an example of such a definition:

\documentclass{article}
\usepackage{amsthm}
\usepackage{lipsum}

\newtheoremstyle{break}
  {\topsep}{\topsep}%
  {\itshape}{}%
  {\bfseries}{}%
  {\newline}{}%
\theoremstyle{break}
\newtheorem{theorem}{Theorem}

\begin{document}

\begin{theorem}[Some note]
\lipsum*[2]
\end{theorem}

\end{document}

enter image description here

answered Dec 10 '11 at 13:47

Gonzalo Medina

505,128

16

Hi, I am trying to do this method and it works for most cases except when I begin \begin{enumerate} right after the theorem. in whcih case it dosnt break – masfenix Mar 04 '13 at 05:26
6

I have just encountered the same problem with \begin{enumerate}. Would be happy for help, or I'll try a different package probably. – quapka Apr 14 '14 at 20:15
Thank you for this helpful answer. I need to further produce a little indent. (After the heading of the theorem, I need to have a new paragraph.) How can I do this? – Ribz Dec 13 '16 at 19:15
2

I found a hack for the itemize/enumerate situation - just add an empty item as the first one – Adam Gal Jul 08 '19 at 12:24
2

Did anyone find solution for \begin{enumerate} situation? – Travis Feb 13 '20 at 03:55
4

@Travis Adam's solution/hack works well: just add \item[] (empty item with an empty label) as your first item. You can also simply start your theorem with \hfill, this works regardless whether you're starting with a list or not. – imakhlin May 16 '20 at 16:09

barbara beeton · Answer 2 · 2021-01-11T20:37:37.717

30

this is a "break" style recommended in the ams' "newtheorem and theoremstyle test" for amsthm:

\newtheoremstyle{break}% name
  {}%         Space above, empty = `usual value'
  {}%         Space below
  {\itshape}% Body font
  {}%         Indent amount (empty = no indent, \parindent = para indent)
  {\bfseries}% Thm head font
  {.}%        Punctuation after thm head
  {\newline}% Space after thm head: \newline = linebreak
  {}%         Thm head spec
\theoremstyle{break}
\newtheorem{thm}{Theorem}

look here for the pdf output and the input for this documentation. the files (named thmtest.*) are also on ctan.

edited Jan 11 '21 at 20:37

answered Dec 10 '11 at 13:44

barbara beeton

88,848

What if I want theorems to be on a new line but propositions on the same line? like theorem 12\\Let $x$ be... but proposition 23: For all $y$... – user5402 Aug 04 '15 at 14:40
@metacompactness -- use a different \theoremstyle. \theoremstyle{plain} is the most appropriate for propositions. (amsthm has three predefined styles; they are described in the documentation.) – barbara beeton Aug 04 '15 at 16:38
Thank you for your help. (I was looking for a solution and I found it here!) But my problem is further complicated. I have a definition (with amsthm) and after the heading of the definition I have like two paragraphs but when I applied your solution I get no indent for the first paragraph. The only way I can fix this is by removing the indent with \noindent of the second paragraph. Can I, instead, make the first paragraph with an indent? Thanks. – Ribz Dec 13 '16 at 19:26
@Riebuoz -- what you're asking is really a new question. please post one, providing a small, compilable example that demonstrates the result you're getting, and a description of how what you want differs. the compilable example means that people here can easily cut and paste the code, making it very easy to experiment. that's the best way to get an answer quickly. you can include a pointer to this question and say how it's relevant. – barbara beeton Dec 13 '16 at 19:49

Theorem environment - line break after label

2 Answers2

Linked