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Re: Unicode and math symbols
> I agree very much with you. However, I read Barbara's comments
> as to that she wants to be closer to semantics than we would.
I too was puzzled by what Barbara meant by "meaning" in the context of
here's the context in which i used "meaning".
unicode (and other codes) deal with *meaning*, not form.
unfortunately, someone has borrowed my (partial) copy of iso 10646,
so i can't check to see how the columns are labeled. but what i
meant here is the words that get put into the description column.
... also, when the same shape
can appear both as an ordinary symbol and as a relation, there are
two different glyphs registered; the justification i used was that
the side bearings are different, since a difference in meaning
same here, except the column in the glyph registry is headed "glyph
name or description". a pure shape description isn't adequate
(although that's often what's present); this also gets into usage
and (minimally) presentation context.
here are several out-of-context quotes from an early version of the
draft character-glyph model generated by members of the u.s. technical
committees x3v1 (counterpart of international sc18/wg8) and x3l2
(international sc2/wg2). these show the association i have with the
meaning of "meaning".
From a historical perspective, few differences have been traditionally
attributed to the notions of "character" and "glyph". If used at all, the
term "glyph" was associated with "the" visual image of a "character". Most
frequently, the term "character" has been (and still is) used to refer to
both a unit of information and a visual shape associated with that unit of
Consider for a moment the case with the unit of information meaning "one".
In ISO/IEC 10646 not only are there a large number of characters which
conceivably "represent" this "unit of information", but there are also a
number of "characters" which represent a particular form associated with
this meaning, i.e., the Arabic digit <1> form itself.
In specifying characters for inclusion in a character set standard, SC2
normally has recourse to the meaning of a character, and, in particular,
has the option of unifying two or more forms if it is determined that those
forms do not represent distinctions in meaning within a particular written
language, or that the forms represent merely stylistic differences. On
the other hand, the glyph registration authority of ISO/IEC 10036 does not
have recourse to such an analysis, and must, if so requested, register
all elements of any font so that a unique identification for all glyph
representations within a font is possible. ... If there is a set of
criteria for distinguishing among two glyphs, it cannot be based on
distinctions in meaning, but distinctions of form.
1. A character conveys distinctions in meaning. A character has no
2. A glyph conveys distinctions in form. A glyph has no intrinsic meaning.
3. One or more characters may be depicted by one or more glyph
representations (instances of an abstract glyph) in a possibly context
This last point spells out the possible relationship between characters and
glyph representations. In its fully general form, this relationship is a
context sensitive M to N mapping, M>0, N>0.
In practice, because ISO/IEC 10646 contains "glyph-like" characters, it is
expected that implementations may choose to "canonicalize" or "normalize"
such characters by translating them to normative characters. A display
subsystem which employs such a technique may require character data be
normalized prior to display.
5.1 - Processing Domains: Content and Appearance
Two primary processing domains may be applied to character information.
The first pertains to the processing of the content, or meaning of the
information; and, the second, to the presentation or imaging of the
(this draft was dated september 1993, and i was part of the joint
committee that drafted it. i should also note that it has changed
a great deal since then, and i haven't seen the most recent versions.)
sorry, i should have been more precise.