# [OS X TeX] blackboard bold semicolon

Alain Schremmer schremmer.alain at gmail.com
Thu Jul 24 09:32:58 EDT 2008

On Jul 24, 2008, at 6:34 AM, Art Werschulz wrote:

> Hi.
>
> On Jul 24, 2008, at 4:25 AM, Ross Moore wrote:
>
>> Hi Art,
>>
>> On 24/07/2008, at 2:17 AM, Art Werschulz wrote:
>>> Hi.
>>>
>>> I am trying to produce a blackboard bold semicolon.  My test file
>>> is as follows:
>>>
>>> <testfile>
>>> \documentclass[12pt]{article}
>>> \usepackage{amsfonts}
>>>
>>> \begin{document}
>>> $R{\mathbb{;}}S$ and $R;S$ should look different (the semicolon
>>> should
>>> be blackboard bold and normal, respectively).
>>
>> Sorry, I cannot agree with you here.
>> What is a "blackboard bold semi-colon" meant to mean?
>> How is it different to a normal semi-colon?
>> If there is a different meaning, where does this occur
>> within existing literature?
>
> I am using the text
>    Neville Dean, "Essence of Discrete Mathematics"  (Prentice-Hall
> PTR, 1996)
> in a course that I'm teaching.  Unfortunately, this text uses a
> blackboard bold semicolon to represent what you might call
> covariant composition of relations, as opposed to the usual $\circ$
> that's used for the standard (contravariant) notation.   I'm giving
> an exam on this material soon; for this particular class, it would
> notation.  So I'm more or less forced to use same on the exam.  :-(

If all else fails, you can always draw it (while zoomed in), save it
as pdf and then define a command to insert it with \includegraphics:

\newcommand{\odiv}{\raisebox{-0.16em}{\includegraphics[scale=0.90]
{odiv}}}

Regards
--schremmer