Theses, Books, Title pages ⇒ Using images inside Theorems

[templateuser]

Hi!
First of all, congratulations and thanks to the creator of this template. It is awesome!!
And here goes my question... Is it possible to include images inside the Theorem environment (or definition, or exercise...)? When I simply put the image inside it the regular way (ie, \begin{figure} \include{graphics}...) I always get the same error: "Lost float"
Many thanks in advance!! Any help will be much appreciated.
Cheers

the_blue_note

[Vel]

Hi,

Putting a float inside a float gives an error as you have said in your post, which means you can't use the figure environment within the theorem environment. Luckily, there is a workaround you can use which is to refrain from using the figure environment and print the caption using the caption package. To do this, you will need to include the caption package in the preamble with \usepackage{caption} and then to include a figure within a theorem, use the following example:

Code: Select all

\begin{theorem}[Name of the theorem]
~\\[12pt]
\includegraphics[scale=0.5]{placeholder}
\captionof{figure}{Caption for image}
In $E=\mathbb{R}^n$ all norms are equivalent. It has the properties:
\begin{align}
& \big| ||\mathbf{x}|| - ||\mathbf{y}|| \big|\leq || \mathbf{x}- \mathbf{y}||\\
&  ||\sum_{i=1}^n\mathbf{x}_i||\leq \sum_{i=1}^n||\mathbf{x}_i||\quad\text{where $n$ is a finite integer}
\end{align}
\end{theorem}

Cheers,
Vel

[templateuser]

Thank you, thank you, thank you!! =)
PS: How do I mark this as closed...?

[Vel]

You're welcome

I usually leave these open so others can come along later and ask further questions on the same topic or add further solutions.

[Johannes_B]

Instead of putting a \newline, i suggest to use a proper paragraph break, maybe even along with a center environment.

Code: Select all

\documentclass{book}
\usepackage{caption}
\usepackage{mathtools}
\usepackage{mwe}
\usepackage{amssymb}
\usepackage{physics}
\newtheorem{theorem}{Theorem}
\begin{document}
\begin{theorem}[Name of the theorem]~
	\begin{center}
	\includegraphics[width=.6\linewidth]{example-image-a}
	\captionof{figure}{Caption for image}
\end{center}
	In $E=\mathbb{R}^n$ all norms are equivalent. It
	has the properties:
	\begin{align}
		& \big| ||\mathbf{x}|| - ||\mathbf{y}||
		\big|\leq || \mathbf{x}- \mathbf{y}||\\
		& ||\sum_{i=1}^n\mathbf{x}_i||\leq
		\sum_{i=1}^n||\mathbf{x}_i||\quad\text{where
		$n$ is a finite integer}
	\end{align}
\end{theorem}
\end{document}

The math could use a lot of polishing using packages like physics and semantic markup as well.