# Re: Another technical question about arrow-building

• To: alanje@cogs.susx.ac.uk, math-font-discuss@cogs.susx.ac.uk
• Subject: Re: Another technical question about arrow-building
• From: yannis@gat.citilille.fr (Yannis Haralambous)
• Date: Wed, 11 Aug 93 21:50:01 +0200

```I realize now that most of answers to questions of this list have perhaps
never been transmitted. So I'll make a summary, if you already have read
all this then just ignore the rest.

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. Although in music this is not the case (as all violonists know),
one can assume that \$\flat\circ\sharp\cong\natural\$, and so the \natural
key can be useful as well. Also I would like to use it for ``forgetful''
operations, that is operations which forget a part of algebraic structure:
going from an algebra to itself as module, from a ring to itself as group etc.

J"prg Knappen made a very important point IMHO by saying that ``people use
some symbols because they are available in \TeX''. I think that this fact
allows us more freedom in the choice of new and original symbols; after all,
selecting the right symbols for the things one wants to express in math is
a fondamental (and very exciting) part of the process of writing (and hence
also *doing*) math.

It woul be nice to investigate the influence of \TeX\ on typesetting and
doing mathematics. The former is easy to see, the latter more hidden but
certainly not trivial. And the most important: I'm sure that Don would be
extremely happy to read the results of such an investigation; it would be a
nice present for the 15 years of \TeX.

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). Any plans of incorporating Michael Spivak's LAMS fonts, now tht
they are in the public domain? or perhaps the work on arrows presented in
Prague?

Cheers again
Yannis

```