# Re: Binary Relations, draft 1

• To: math-font-discuss@cogs.susx.ac.uk
• Subject: Re: Binary Relations, draft 1
• From: Hans Aberg <haberg@matematik.su.se>
• Date: Tue, 17 Nov 1998 18:30:38 +0100
• Content-Length: 1354

At 13:57 +0000 1998/11/17, Martin Ward wrote:
>I have seen (and used) an "=" with a small subscript "DF" for definitions.
>In TeX I use:
>
>\def\edf{\mathrel{\;=_{{}_{\mbox{\rmtiny DF}}}\;}}
>
>since an ordinary subscript DF is still too big.

\def\edf{\mathrel{\;=_{{}_{\tiny\mathrm{DF}}}\;}}
in LaTeX2e.

It looks nice, but I am not sure everybody seeing will be able to
understand it without explanation. -- I think that variations with "def"
might be more standard.

The main point for Unicode I presume is whether people need and use it
_semantically_ (specifically an asymmetric definition symbol). -- Then the
variations are different renderings of the same semantic symbol.

My impression, indeed people use such asymmetric definition symbols. So
perhaps Unicode should supply such symbols. Then the binary relation "134
225D eqdef" symbol (an "=" with the word "def" above) should remain as it
is: It is a sort of generic symbol for the different types of definitions
that one would use when one does not want to bring out the specific details
about which of the other types of definitions it represents.

Hans Aberg
* Email: Hans Aberg <mailto:haberg@member.ams.org>