Using thmtools to make colored theorem style

Question

I am trying to define a new theorem style that is identical to the standard remark provided by the amsart class, except for its color. As far as I understood, it is a good idea to use the thmtools package. However, I do not know what options I should include in the command \declaretheoremstyle to produce the usual remark style from amsart.

Below is my attempt. As you can see, the result is not satisfactory because the vertical spacing before and after the remark changes slightly. Does anybody know how to solve this?

\documentclass{amsart}
\usepackage{xcolor}
\usepackage{thmtools}
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\theoremstyle{remark}
\newtheorem{remark}[theorem]{Remark}
\declaretheoremstyle[headfont = \color{red}\normalfont\itshape, bodyfont = \color{red}\normalfont\itshape]{colored}
\declaretheorem[sibling = theorem, style = colored, name = Remark]{coloredremark}
\begin{document}
\begin{theorem}
Body of first theorem.
\end{theorem}
\begin{coloredremark}
Body of colored remark.
\end{coloredremark}
\begin{theorem}
Body of second theorem.
\end{theorem}
\begin{remark}
Body of normal remark.
\end{remark}
\begin{theorem}
Body of last theorem.
\end{theorem}
\end{document}

score 2 · Accepted Answer · answered Jun 07 '21 at 20:50

2

You don't really need to use thmtools for that. Since you want a style similar to a default style provided by amsart, it's even simpler to use \newtheoremstyle, which is defined by AMS classes and by amsthm.

To see how to use \newtheoremstyle, see the section 4.3 of the documentation, on page 9. Here's an example that should work.

\documentclass{amsart}
\usepackage{xcolor}
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\theoremstyle{remark}
\newtheorem{remark}[theorem]{Remark}
\newtheoremstyle{coloredremark}%
    {}%
    {}%
    {}%
    {}%
    {\itshape\color{red}}%
    {.}%
    {.5em}%
    {}%
\theoremstyle{coloredremark}
\newtheorem{coloredremark}[theorem]{Remark}
\begin{document}
\begin{theorem}
Body of first theorem.
\end{theorem}
\begin{coloredremark}
Body of colored remark.
\end{coloredremark}
\begin{theorem}
Body of second theorem.
\end{theorem}
\begin{remark}
Body of normal remark.
\end{remark}
\begin{theorem}
Body of last theorem.
\end{theorem}
\end{document}

answered Jun 07 '21 at 20:50

Vincent

20,157

Thanks for the help! Avoiding thmtools would be even better. The problem is that when I try to color also the body font, extra vertical spaces appear. One should thus set appropriate values for the space above and the space below. – Matteo Raffaelli Jun 07 '21 at 21:16
Do you know which values I should choose? – Matteo Raffaelli Jun 07 '21 at 21:21
@MK7 leaving the first two arguments blank (as I did in the example) will use the default values for the spaces above and below. Did you try as in the example? – Vincent Jun 08 '21 at 01:18
Yes, I did! But I also need the body of the remark to be red. If I add \itshape\color{red} in the third argument and leave the first two blank, then extra vertical spaces appear. Am I missing something? – Matteo Raffaelli Jun 08 '21 at 07:25
It works by adding .5\topsep in the first and second arguments. That is the default value of the remark style, as indicated in this answer. – Matteo Raffaelli Jun 08 '21 at 08:15

Using thmtools to make colored theorem style

1 Answers1