Title: How to change dot to colon after theorem in amsthm?
Tags: environments;theorems;amsthm
Question: How do I change the dot to a colon in a theorem environment?
Minimal Working Example:
\documentclass{book}
\usepackage{amsthm}
\newtheorem*{test}{Test}
\begin{document}
\begin{test}
\end{test}
\end{document}
Not a duplicate of
Can I change the dot to a colon after Proof in amsthm?
since neither answers there work.

Here is the accepted answer: You can define a new style:
\documentclass{book}
\usepackage{amsthm}
\newtheoremstyle{colon}%
{\itshape}%bodyfont
{}%indent
{\bfseries}%headfont
{:}%head punctuation
{ }%space after head
\theoremstyle{colon}
\newtheorem*{test}{Test}
\begin{document}
\begin{test}
Blah blah blah.
\end{test}
\end{document}

Here is another answer: You can define a new theorem style like this:
\newtheoremstyle{mystyle}% name of the style to be used
{}% measure of space to leave above the theorem. E.g.: 3pt
{}% measure of space to leave below the theorem. E.g.: 3pt
{}% name of font to use in the body of the theorem
{}% measure of space to indent
{}% name of head font
{:}% punctuation between head and body
{ }% space after theorem head; &quot; &quot; = normal interword space
{\thmname{#1}\thmnumber{ #2}\thmnote{ #3}}
\theoremstyle{mystyle}
Just add this before the first use of \newtheorem.
Source: https://en.wikibooks.org/wiki/LaTeX/Theorems

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