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

From: Martin Duerst <duerst@w3.org>
Date: Tue, 02 Apr 2002 18:06:07 +0900
Message-Id: <>
To: www-math@w3.org
Cc: unicore@unicode.org, ion@ams.org, bnb@ams.org, w3c-i18n-ig@w3.org, asmusf@ix.netcom.com, kenw@sybase.com
Dear MathML WG,

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

I haven't found these at http://www.w3.org/2001/02/MathML2-errata.

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,
(see http://www.unicode.org/reports/tr28/#13_7_variation_selectors)
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 http://www.w3.org/TR/MathML2/variants.html
>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

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