Re: Superscript asterisk

From: Jonathan Coxhead (jonathan@doves.demon.co.uk)
Date: Thu Jul 01 1999 - 18:38:57 EDT


 | We finally settled on adding a set of "Math Styled Alphabets" to the
 | surrogate space (Plane 1 in 10646), or about 1000 characters from the
 | base Latin and Greek alphabets, plus digits, in only those style /
 | case combinations as are actually used in the mathematical
 | literature. We are in active collaboration with a consortium of
 | mathematicsl publishers, including the American Mathematical Society
 | (AMS), so we are pretty confident that the set we have picked is
 | indeed the set of Letterforms used by mathematicians as distinct
 | elements for symbolic notation.

   I must admit to a degree of astonishment here ... Isn't this exactly
the sort of combinatoric explosion that the existing combining marks
were intended to defeat?

 | One of the drawbacks of your
 | proposal is that it is open ended in that regard, i.e. it is a
 | complete style markup (just add font size ;-).

   I saw this as an advantage, in fact. Font size is already present:
PRESENTATION SUGGESTION SMALL/WIDE are there. The first is useful in
text with lots of acronyms, for example.

   So does this mean that there will be separate characters encoding
'X' as italic, bold, bold italic, fraktur, script, double-struck? (Plus
others I may not be aware of?) And then also bold versions of COMBINING
DOT ABOVE, COMBINING DIAERESIS, etc? (These are normally used with bold
'X' to indicate velocity, acceleration, resp.)

   And then superscript and subscript versions of all these (and
presumably supersuperscript, supersubscript, subsuperscript and
subsubscript as well)? (Including combining marks?)

   And I'd guess there'd be a need for left- and right-half tilde and
circumflex accents, because these can be used to bridge a character-
pair together, and with no START GROUP character, the possibility of
using

      start group
         latin small letter a, presentation suggestion italic,
         latin small letter b, presentation suggestion italic,
      pop directional formatting,
      combining tilde

is gone.

   This is fabulous!

 | It is generally not a good idea to introduce such elements as
 | characters because they blur the line between text content and text
 | markup and create contentions and inconsistencies between information
 | at one level and information at another.

   This is a line that is already fairly blurred.

   But my suggestion involves solving *no* new problems, because the
relationship between '<i>x</i>' (H T M L markup) and 'latin small
letter x, presentation suggestion italic' is exactly analagous to the
relationship between

      <span dir = rtl>Rtl</span>

("high-level markup" form) and

      right-to-left override,
         latin capital letter r,
         latin small letter t,
         latin small letter l,
      pop directional formatting

("low-level character encoding" form), which you have to be able to
deal with sensibly already.

   However, I shall endeavour to get to the conference in San
Jose---it's all of 10 miles down the road :-)

   Just for amusement, here's another plain-text formula:

      / N
      | dx
      | --
      | x
      / x = 0

(that's supposed to be an integral). With just those 13 characters, we
can write

      integral,
      start group,
         latin small letter x, presentation suggestion italic,
         equals,
         digit zero,
      pop directional formatting,
      presentation suggestion subscript,
      latin capital letter n,
      presentation suggestion superscript,
      start group,
         latin small letter d,
         latin small letter x, presentation suggestion italic,
      pop directional formatting,
      fraction slash,
         latin small letter x, presentation suggestion italic.

   (You might see this as 'Sx=0Ndx/x', if your rendering agent is
particularly dim. But that might be enough.)

   It seems to me that this is infinitely more elegant than a solution
involving hundreds of new codings of Latin and Greek (and Hebrew)
characters.

        /|
 o o o (_|/
        /|
       (_/



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