visual presentation of prime accents

The term prime accents refers to Unicode points ′ (U-2032),
″ (U-2033), ‴ (U-2034), &backprime (U-2035), and ⁗
(U-2057).  All of these data points are presentable in ordinary (i.e.,
non-MathML) XHTML or XML text, and for that context visual
presentation handling appears to be standard.

In some user agents it appears that under certain conditions, various
ASCII constructions inside MathML such as ','',''',`, ... are given
equivalent visual presentation.

The examples given in the W3C MathML Test Suite are relevant:

The MathML Spec (version 21 October 2003) alludes to the presentation
handling of prime accents in MathML only very casually at section

There is inconsistent handling among the various accents in some user
agents, and between different agents.  At this point I find it
unclear what should be regarded as normative.

The matter is somewhat complicated.  For a more elaborate presentation
of these thoughts please see

The discussion is mostly oriented around Firefox's presentation, but
the examples there may be viewed with interest in other user agents,
and the comment is relevant to further thought about what should be

The MathML specification needs more work in regard to the prime accents.

                                    -- Bill

Received on Sunday, 14 January 2007 04:43:27 UTC