# Re: Another technical question about arrow-building

• To: math-font-discuss@cogs.susx.ac.uk
• Subject: Re: Another technical question about arrow-building
• From: alanje@cogs.susx.ac.uk (Alan Jeffrey)
• Date: Wed, 11 Aug 93 21:00 BST

```>Justin asked about the \flat and \sharp. I replied that I have used both
>of them in my thesis (Algebraic Topology) to denote duality between algebraic
>structures.

Yes, the `abstract nonsense' crowd are very into \flat, \sharp and
\natural.  They're common enough in that field to be strong contenders
for inclusion in an MSi encoding.  I don't think they're dependent
enough on the MC font shape to deserve going into MC (fortunately,
since space in MC is going to be precious!)

>It woul be nice to investigate the influence of \TeX\ on typesetting and
>doing mathematics.

I think that would be a very nice and very useful paper.  I'm sure
that TeX has has quite an influence on the choice of mathematical
notation of the last 10+ years.  Any volunteers?

One example of TeX's influence (IMHO) is the choice of different
mathematicians to use \$\bigsqcup\$ or \$\bigvee\$ to mean `lattice join'.
Partly this is tradition, but partly I expect that the lack of a
\$\bigsqcap\$ in cmex meant that anyone who stepped from the theory of
complete semi-lattices to the theory of lattices would suddenly need
to use \$\bigvee\$ and \$\bigwedge\$!  So CS and domain theory types (who
don't use meet very much) stick with \$\bigsqcup\$ whilst the lattice
theorists use \$\bigvee\$...

>In another message I was asking about oblique arrows (in category theory and
>algebraic topology they [oops, I almost said ``we''...] need them a lot for
>diagrams).

Yes, there is a need for diagonal arrows, the question is how much
should be covered by the vanilla math fonts, and how much should be
left to the commuting diagrams package.  I expect the final answer
will depend on how many free slots there are in MX!

>Any plans of incorporating Michael Spivak's LAMS fonts,

Are these up for anonymous ftp from somewhere?

>or perhaps the work on arrows presented in Prague?

Ditto?

Alan.

```