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Re: Math Arrows and Harpoons, Draft Three

(I, and perhaps some others, are not on the group tex-nl@nic.surfnet.nl, so
any responses on this topic there relevant to the
math-font-discuss@cogs.susx.ac.uk group needs to cc this one.)


At 23:01 +0100 1998/11/14, Taco Hoekwater wrote:
>I just uploaded a new draft of the arrows&harpoons font
>to my web page:
>
>   http://www.cybercomm.nl/~bittext/fonts/arrows.html
>
>This is draft three, with a lot of improvements ...

On the arrows 000-003 and the short arrows (or arrowhead components)
011-014, I can not recall any math situation where the length of an arrow
has any semantic significance.

>	  - redesigned triangle heads

The arrows 114-116 I think now looks much better. I can note however that
the back of these arrowheads are now bent in the opposite of the regular
arrowheads (009,002,004).

>	  - angled and flat headed wavy arrows

On the two series 069-171 versus 164-166, and 125-126 versus 127-128, I am
still inclined to believe that these are just different renderings of the
same symbol.

  The design variations all look good though: I would prefer 069-171 over
164-166. For the bent arrows, I could not recall any mathematical usage (I
looked through a book on category theory, and it did not have it); I know
that 125/127 can be used to denote an ASCII return on computers.

  I am not sure this is all logical: For example one the arrows 129/174,
they look semantically the same to me. I would prefer a variation looking
more like 129, except that I would not require it to be an exact
semicircle, just a bend -- so therefore something like 174 would be
acceptable to me. In addition, I would use this kind of arrows as a
variation of the plain arrow 002, so therefore 174 seems to be acceptable
to me (it should then come with a mirror reversed version).

  On 137-138, one use is in closed line integrals in physics (even though
these integral signs probably have separate symbols). So it could be that
these should be fully closed circles with an arrowhead onto. In the case of
the line integrals, the arrowhead should be to the side, not the top, in
order to not be in the way of the integral sign symbol.

  The two arrows >->> and <<-< seem to not be present: These are used in
category thoery to indicate that a homomorhism is both mono and epi (and
thus iso in say an Abelian category). (Thus a head like in 015/017 and a
tail as in 009-010.)

  Hans Aberg
                  * Email: Hans Aberg <mailto:haberg@member.ams.org>
                  * Home Page: <http://www.matematik.su.se/~haberg/>
                  * AMS member listing: <http://www.ams.org/cml/>