Consider the following MWE:
\documentclass[]{report}
\usepackage{amsthm}
\makeatletter
\def\th@definition{
\thm@notefont{}
\bfseries}
\makeatother
\newtheoremstyle{definition}{2.5em}{2.5em}{}{}{\bfseries}{}{1em}{}
\theoremstyle{definition}
\newtheorem*{defn}{Definition}
\begin{document}
\begin{defn}[Optional Title] Definition content.
\end{defn}
\end{document}
I want to keep the updated definition style, but have the optional title in bold. The first few lines of code (makeatletter ... makeatother) accomplish this for the default definition, but they stop working when I try to modify the definition style. How can I fix this? Thanks in advance.
\makeatletter...\makeatotherupdate precedes\newtheoremstyle{definition}, which overwrites your\th@definition. So, technically, the former construct is useless. So what do you mean by "updated definition style"? – Werner Jun 16 '14 at 16:35definitiontheorem style after that, as noted by @Werner, so if you stick with this definition, you should reverse the order. but it would really be better if you did not redefine an existing style -- that will only confuse someone else if they have to look at it later. – barbara beeton Jun 16 '14 at 16:49