Comments on the Unicode Codepoints and IDNA Internet-Draft

[Kent Karlsson]

Frank Ellermann wrote:

> >> There is a reason why many code points such as "mathematical
> >> fraktur capital B" or "black-letter capital C" are disallowed.
...
> I'd guess that those two code points are not really letters in
> an Unicode sense,


They are letters, but they cannot be part of a string in NFKC form
since they have compatibility mappings to the corresponding nominal
uppercase letters. They also have to-lower mappings to the corresponding
"faktur" lowercase letters (which also have compatibility mappings
to the corresponding nominal lowercase letters).

		/kent k