Errata on MathML (was: Re: UTC Agenda Item: Variation Selection Problem)

Dear MathML WG,

This is an errata report from the Unicode consortium's
internal technical mailing list.

I haven't found these at

I'm acting as the liaison from the W3C I18N WG to the Unicode
Consortium, and have copied the I18N IG.

For background, the discussion started because there is a note
in Unicode 3.2 that variant selectors cannot be used for
decomposable characters, to avoid normalization problems,
but there are two cases where this is not respected, which
lead to the following proposal:

Especially in light of the fact that there is an already-encoded way
to express the variation, the UTC should issue a corrigendum removing
the variant sequences <2278, FE00> and <2279, FE00> and request that
WG2 do the same in a corrigendum to 10646.

At 10:42 02/03/29 -0800, Kenneth Whistler wrote:
> > See
>Yes it does (have an impact on MathML).

>which *does* deal with the two characters and two variants
>in question, and botches those, as well.
>In particular, the slanted cancellation of U+2276 is defined
>as <U+2276, U+0338> (correct), but the vertical cancellation
>is defined as U+2278 (incorrect). U+2278 is canonically
>equivalent to <U+2276, U+0338> -- and what they *should* have
>in the table is <U+2276, U+20D2> for the vertical cancellation.
>Same issue for the cancellations of U+2277.

>Incidentally, the MathML tables also make the nonsanctioned
>extension of all character short identifiers to 5 digits
>(defined neither by the Unicode Standard nor Clause 6.5 of

I think the standard form is to use either four digits or
six digits, is that correct?

> > But we should make
> > >sure that the deletion of these two variant sequences from our
> > >standard would get reflected accurately into MathML, and that the
> > >mapping for the not-less-than-or-greater-than-with-vertical-bar,
> > >etc. entities get handled correctly.
>I repeat that this needs to be done.
>Any by the way, is *anybody* minding the store over there in
>MathML? How do W3C Recommendations get published with blatant
>errors in their use of the Unicode Standard and 10646?

There is a Math Working Group, and one of its tasks is to take
care of errata. And there is the I18N WG/IG, which is doing
general review work with respect to Internationalization
(which often includes Unicode-related issues), but the mapping
details were left to the experts in the Unicode Consortium and
the Math Working Group.

Regards,    Martin.

Received on Tuesday, 2 April 2002 08:10:39 UTC