Here's my summary of the annotations that we've been discussing so far:
U+003A COLON
* also used to denote division or scale, for that usage 2236 : RATIO is
preferred
U+00B7 MIDDLE DOT
* also used to denote multiplication, for that usage 22C5 · DOT OPERATOR
is preferred
U+2052 COMMERCIAL MINUS SIGN
x 00F7 division sign
U+22C5 DOT OPERATOR
* Used in preference to 00B7 · to denote multiplication
U+2236 RATIO
* Used in preference to 003A : to denote division or scale
U+00F7 DIVISION SIGN
= obelus
* also used as an alternate, more visually distinct 2212 - MINUS SIGN or
2011 – EN DASH in some contexts
* historically used as a punctuation mark to denote questionable
passages in manuscripts
x 070B syriac harklean obelus
x 2212 minus sign
x 2052 commercial minus sign
(the reference to en-dash is based on the Italian usage cited in the
wikipedia article for Obelus)
The discussion of these symbols in the relevant chapters of the standard
could also be improved.
On page 200, the subsection "Other Punctuation" should be augmented by
this sub-sub-section
/Obelus/ Originally a punctuation mark to denote questionable passages
in manuscript, U+00F7 DIVISION SIGN is now most commonly used as a
symbol indicating division. However, even modern use is not limited to
that meaning. The character can be found as indicating a range (similar
to the /en-dash/) or as a form of /minus sign/. The latter use is still
widespread in Scandinavian countries. (see also "Commercial Minus").
On page 203 after "Scandinavia" add "(see also Obelus)".
On page 202 of chapter 6 add under "Other..."
Several punctuation marks, such as COLON, MIDDLE DOT and SOLIDUS closely
resemble mathematical operators, such as U+2236 RATIO, U+22xx DOT
OPERATOR and U+22xx DIVISION SLASH. The latter are the preferred
characters, but the former, being more easily typed, are often substituted.
On page 511 of chapter 15 add in "Semantics" after "context".
"For some common mathematical symbols there are also local variations in
usage. For example, U+00D7 DIVISION SIGN, besides having a long history
of use as punctuation mark, is also used in certain cases to indicate
negative numbers in several European countries."
It might be worth mentioning U+00D7 MULTIPLICATION SIGN in chapter 15.5,
because it's arguably a mathematical operator, even though not encoded
in the standard blocks of operators.
/Mathematical Operators In other Blocks/
A small number of mathematical operators and related characters in
common use have been encoded in other blocks. These include U+002B PLUS
SIGN, U+00D7 MULTIPLICATION SIGN and U+00F7 DIVISION SIGN, as well as
003C GREATER THAN, 003D EQUALS SIGN and 003E LESS THAN. The /factorial
operator / is unified with U+0021 EXCLAMATION MARK
A./
Received on Tue Jul 10 2012 - 17:25:14 CDT
This archive was generated by hypermail 2.2.0 : Tue Jul 10 2012 - 17:25:16 CDT