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Re: Math Arrows and Harpoons

>>>>> "HA" == Hans Aberg <haberg@matematik.su.se> writes:

 HA> At 17:42 +0100 1998/11/11, Taco Hoekwater wrote: In general, all
 HA> symmetry cases for binary relations and arrows and such should be
 HA> added, becuase at some point one may need it in mathematics: It
 HA> proves to be difficiult to find such symbols which are good and
 HA> readable, so these symbols will surely show up in new contexts.
 >>  I would prefer something a little bit more specific. There are so
 >> many possible symmetry cases that we might end up with a full font
 >> that contains only harpoons...
 >> 
 >> Lots of the "missing cases" are already in the STIX tables for
 >> precisely this reason, but there is just not enough room to
 >> capture all possible cases.

 HA> I think this is the problem with treating such symbols as
 HA> characters and putting them into a character font: One should
 HA> have some more general underlying mechanism describing them.

This is true, but does not apply to Unicode character tables.  The
idea is: every specific currently used *meaning* should have a
character/glyph pair to go with it. Sure the font will contain some
"build it yourself" characters, but these cannot be submitted to
Unicode for precisely the above reason.

 HA>   In the absence of this, perhaps there should be two fonts, one
 HA> for arrows and symbols which are complete, and one for arrows
 HA> described as components (head, tail, stem).

See my other e-mail message.


 >> The sidebearings for the fish tails and the arrow tails are
 >> unclear to me.  Are these extensions to other characters or are
 >> they stand-alone relations?

 HA>   If you mean characters such as 88 and 116, I feel pretty sure
 HA> they are exclusively used as a components of a larger character
 HA> and never standalone.

Combining your and Barbara's comments, this gives me the impression
that I also need to provide the fish tails as building blocks (not a
problem, just noting).

 >> Are chars 193--198 correct interpretations X "over" Y

 HA>   I am not sure what you mean here: interpretation relative to
 HA> what? If you simply mean if an arrow stem drawn above another

Relative to the formal description, which uses the word "over". But
I'm quite happy with this rendering. The bended version looks outdated
in print, I think.

Greetings, Taco