# [texhax] [tug support aka texhax] formatting equation numbering

Donald Arseneau asnd at triumf.ca
Tue May 27 06:05:34 CEST 2014

On Mon, May 26, 2014 5:06 am, Makai Mihály wrote:

> Thanks, it has worked. How can one put the equation number in bold?

>>> Is it possible to change the style of equation numbering in the
>>> amsbook.cls package?
>>
>> So copy the definition used by amsbook.cls, which is to be
>> found in amsmath.sty, and redefine it slightly differently.

Yes, in the way you would normally make something bold faced.

The tag (or number) itself is the parameter #1; the parentheses
or brackets are there to be seen; the scarey-looking commands
\ignorespaces ... \unskip\@@italiccorr are details that are not
terribly important (\ignorespaces ... \unskip allows you to
include spurious spaces in the tag (number) that are not printed,
as with: \tag { X }, and \@@italiccorr prevents collisions if
the tag is slanted or italic.)

So if you want just the number bold, then

\def\tagform@#1{\maketag@@@
{(\textbf{\ignorespaces#1\unskip\@@italiccorr})}}

and if you want bold parentheses

\def\tagform@#1{\maketag@@@
{\textbf{(\ignorespaces#1\unskip\@@italiccorr)}}}

For clarity, those are approximately

\def\tagform@#1{\maketag@@@{(\textbf{#1})}}\def\tagform@#1{\maketag@@@{\textbf{(#1)}}}

It is tricky reading those braces and parentheses.

If all you want to change is the font, then maybe it is better
to redefine \maketag@@@, where the font is normally (no pun
intended) declared, changing

\def\maketag@@@#1{\hbox{\m at th\normalfont#1}}

to

\def\maketag@@@#1{\hbox{\m at th\normalfont\bfseries#1}}

Donald Arseneau, TRIUMF CMMS, asnd at triumf.ca