Too narrowly defined: DIVISION SIGN & COLON

  Problem:

Unicode does not acknowledge

* that the DIVISION SIGN in the (human) mathematical notation of
  at least one language (Norwegian) functions as a stylistically
  distinct MINUS sign.

* that the COLON sign in the mathematical notation of many
  languages functions as a DIVISION sign.

  I. "Division-minus"

In some contexts of the Norwegian (and other Scandinavian?) languages,
one might use DIVISION SIGN (÷) instead of the MINUS SIGN. 3 examples
of use: 1) Teacher draws minus signs on blackboard. 2) An ad about
about a big rebate tells that the price is minus 50% (÷50%). 3) The
'about' text for the Norwegian 'Accounts terminology' standard explains
it clearly why it might be done in books too: [1]

[Translation:] "In the formulas, the minus sign ÷ (instead of -)
                is used to avoid confusion with the hyphen."

This last note perhaps indicates that the 'divsion-minus' (as I will
call it) is used in contexts where math and text are mixed, but where
the emphasis is that a quick glance shall be enough to understand what
is meant. The 'division-minus" in ads were perhaps more common before,
but are still not hard to find. [2][3][4][5] Sometimes the
'divsion-minus' really *does* simplify then interpretation! [6] Some
might say that we are just using the COMMERCIAL MINUS (⁒). However, to
a Norwegian, the commercial minus most certainly looks more like a
percentage character, than as a minus!

   II. Division as colon

   Strikingly, while the Norwegian Nynorsk wikipedia article on
'division in mathematics' mentions the division sign,[7] the equivalent
Norwegian Bokmål article currently does not mention it at all.[8] This
reason is that Norwegians almost exclusively use the colon character
(:) as division sign - which both of the Norwegian Wikipedias articles
therefore mention. A very quick browse of Wikipedia showed me that the
colon as division sign is common in Ukraine, Russia, Sweden and Germany
too. (Thus, English Wikipedia fittingly acknowledges that 'In some
non-English-speaking cultures, "a divided by b" is written a : b.' [9])

   III. Conclusions: Proposal for next Unicode update

Proposal 1:
  EITHER division sign should be renamed to division-minus sign.
      OR a new "double dotted minus" character should be added.

Proposal 2:
  EITHER the COLON should be baptized colon-division character.
      OR a new 'division colon' should be added.
        (The RATIO character and Z NOTATION TYPE COLON cannot
         be rebaptized.)

NOTE: The pattern for the EITHER variants, is the double meaning of the
'hyphen-minus' character. The pattern for the OR variants, is the
singled out 'division slash' character.

[1]
<http://www.standard.no/en/Search-and-buy/ProductCatalog/ProductPresentation/?ProductID=231442>
[2] <http://klinikkoslo.no/files/5913/3907/3752/tilbud_i_juni.jpg>
[3] <http://goo.gl/3vZeT>
[4] <http://www.dustorealpakka.com/blogg/salg-2/>
[5]
<http://kvadrat.no/spesialbutikker/brilleland/50-rabatt-pa-alle-hostens-brillenyheter-hos-brilleland/>
[6]
<http://www.magneten-senter.no/wordpress/wp-content/uploads/2011/07/Salg-helside-nett.jpg>
[7] <http://nn.wikipedia.org/wiki/Divisjon_i_matematikk>
[8] <http://no.wikipedia.org/wiki/Divisjon_(matematikk)>
[9] <http://en.wikipedia.org/wiki/Division_(mathematics)#Notation>

-- 
Leif halvard silli