# Specification in theorem environment also bold

I'm using the following packages/options in my article:

\documentclass[b4paper,12pt]{article}
\usepackage[english]{babel}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{hyperref}
\usepackage{graphicx}
\usepackage{color}

\newtheoremstyle{break}
{\topsep}{\topsep}%
{\itshape}{}%
{\bfseries}{}%
{\newline}{}%
\theoremstyle{break}

\newtheorem{theorem}{Theorem}%[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{definition}{Definition}

\begin{definition}[Test]
This is a test definition
\end{definition}


I would like to have the name (here 'Test') not only in parentheses but also boldface. How can I achieve that?

Thank you!

-

Your amsthm specification for the break theorem style should look like this:

\makeatletter
\newtheoremstyle{break}
{\topsep}{\topsep}%
{\itshape}{}%
{\bfseries}{}%
{\newline}
{\thmname{#1}\thmnumber{\@ifnotempty{#1}{ }\@upn{#2}}%
\thmnote{ {\bfseries(#3)}}}%
\makeatother


The header is managed using the ninth argument. I've just copied it from the amsmath source and replaced the note font with \bfseries. If you leave it empty, it defaults to the plain theorem header style.

Here's your original MWE with the above modification:

\documentclass[12pt]{article}
%\usepackage[english]{babel}
%\usepackage{amssymb}
%\usepackage{amsmath}
%\usepackage{amsfonts}
\usepackage{amsthm}% http://ctan.org/pkg/amsthm
%\usepackage{hyperref}
%\usepackage{graphicx}
%\usepackage{color}

\makeatletter
\newtheoremstyle{break}
{\topsep}{\topsep}%
{\itshape}{}%
{\bfseries}{}%
{\newline}
{\thmname{#1}\thmnumber{\@ifnotempty{#1}{ }\@upn{#2}}%
\thmnote{ {\bfseries(#3)}}}%
\makeatother
\theoremstyle{break}

\newtheorem{theorem}{Theorem}%[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{definition}{Definition}
\begin{document}
\begin{definition}[Test]
This is a test definition
\end{definition}
\end{document}

-
Thank you! This is exactly what I was looking for. I couldn't figure it out by looking for it in the source code...thanks for the help! –  Newby1 Jun 5 '12 at 19:09