Adding vertical space between theorem numbering line and theorem text

Question

When using \begin{theorem} with amsmath, the theorem text is inserted on the same line. I would like to have the text in a new paragraph

Have thought about using \vspace and use a pre-defined vertical spacing. Have seen that the value of \parskip is 0pt. What other predefined separator can I use?

Notwithstanding, \vspace is not inserting a newline.


    \begin{theorem}[{\bf \color{blue} Convolution Property of Fourier Transform}]
      \label{convolution}
  \vspace{5pt}
  \textcolor{blue}{This text in not placed as a new paragraph.}

\end{theorem}

It depends on what packages you are using and document class, different packages or classes can alter it. In plain TeX, it is apparently \parskip=0pt plus1pt or so the TeXbook says (p. 104). Please clarify your question including what class etc — , Apr 23 '22 at 17:45
The value of \parskip is \parskip. So \vspace{\parskip} or what else have you in mind? — Peter Wilson, Apr 23 '22 at 18:11
You should clarify your question. As Peter says, you can do \vspace{\parskip} but in book that has a natural size of 0pt so why would you need his? — David Carlisle, Apr 23 '22 at 18:21
Also, if you're adding \vspace, you should do it only when you're in vertical mode; otherwise, where it's actually applied may surprise you. — barbara beeton, Apr 23 '22 at 18:31
I am using \begin{theorem} and want to have some small vertical space between the theorem numbering, and the theorem text. — Veak, Apr 23 '22 at 18:37
(1) Theorems have nothing to do with amsmath. (2) The theorem environment is defined to begin in horizontlal mode after the header. To get to a new line, you have to break into vertical mode. (3) Although this q/a refers to a proof environment and uses amsthm, the tactics described here will also apply to the theorem environment: Proof environment - line break after the “Proof.” — barbara beeton, Apr 23 '22 at 21:15

score 0 · Accepted Answer · answered Apr 23 '22 at 19:21

This answer is producing the following output:

Using \medskip etc within the environment wouldn't work nor would using it after the command \\ so instead a custom command named \custskip was defined to do as you seek, you can change the 6pt to whatever you would like. As an aside, \bf is quite old so you should use the new commands either \textbf for text in an argument and \bfseries as a switch (i.e. all the text afterwards is bold).

\documentclass{book}
\usepackage{amsmath}
\usepackage{xcolor}
\newtheorem{theorem}{Theorem}
\newcommand\custskip{\[6pt]}
\begin{document}
\begin{theorem}[{\color{blue}\textbf{Convolution Property of Fourier Transform}}]
  \label{convolution}

  \textcolor{blue}{\custskip This text in now placed as a new paragraph.}

\end{theorem} 


\end{document}

Not sure if this is the best or most accurate method but it works.

score 0 · Answer 2 · answered Apr 23 '22 at 21:28

You could do that quite easily with the ntheorem package, which defines a break style:

\documentclass{article}
\usepackage{xcolor} 
\usepackage{blindtext}
\usepackage{amsmath}
\usepackage[thmmarks, thref, amsmath]{ntheorem}
\theoremstyle{break}
\theoremheaderfont{\upshape\bfseries}
\theorembodyfont{\itshape}
\newtheorem{theorem}{Theorem}
\begin{document}
\begin{theorem}[{\color{blue} Convolution Property of Fourier Transform}]
  \label{convolution}
  \textcolor{blue}{This text is placed as a new paragraph.}
\end{theorem}
\end{document}

Adding vertical space between theorem numbering line and theorem text

2 Answers2