From: <juanrgonzaleza@canonicalscience.com>

Date: Mon, 24 Apr 2006 04:38:51 -0700 (PDT)

Message-ID: <3118.217.124.69.210.1145878731.squirrel@webmail.canonicalscience.com>

To: <www-math@w3.org>

Date: Mon, 24 Apr 2006 04:38:51 -0700 (PDT)

Message-ID: <3118.217.124.69.210.1145878731.squirrel@webmail.canonicalscience.com>

To: <www-math@w3.org>

A couple of citations to MathML 2.0 specification <blockquote> 3.1.1 What Presentation Elements Represent Presentation elements correspond to the "constructors" of traditional mathematical notation - that is, to the basic kinds of symbols and expression-building structures out of which any particular piece of traditional mathematical notation is built. Because of the importance of traditional visual notation, the descriptions of the notational constructs the elements represent are usually given here in visual terms. However, the elements are medium-independent in the sense that they have been designed to contain enough information for good spoken renderings as well. Some attributes of these elements may make sense only for visual media, but most attributes can be treated in an analogous way in audio as well (for example, by a correspondence between time duration and horizontal extent). [...] Certain MathML characters are used to name operators or identifiers that in traditional notation render the same as other symbols, such as ⅆ, ⅇ, or ⅈ, or operators that usually render invisibly, such as ⁢, ⁡, or ⁣. These are distinct notational symbols or objects, as evidenced by their distinct spoken renderings and in some cases by their effects on linebreaking and spacing in visual rendering, and as such should be represented by the appropriate specific entity references. </blockquote> <blockquote> 6.3.1 Special Constants To begin we list separately a few of the special characters which MathML has introduced. These now have Unicode values. Rather like the non-marking characters above, they provide very useful capabilities in the context of machinable mathematics. [...] Entity name Unicode Description [...] ⅆ 02146 d for use in differentials, e.g. within integrals [...] </blockquote> <blockquote> The reasons for using specific mo elements for invisible operators include: * such operators should often have specific effects on visual rendering (particularly spacing and linebreaking rules) that are not the same as either the lack of any operator, or spacing represented by mspace or mtext elements; * these operators should often have specific audio renderings different than that of the lack of any operator; * automatic semantic interpretation of MathML presentation elements is made easier by the explicit specification of such operators. [...] 3.2.5.6 Names for other special operators MathML also includes ⅆ for use in an mo element representing the differential operator symbol usually denoted by "d". The reasons for explicitly using this special entity are similar to those for using the special entities for invisible operators described in the preceding section. </blockquote> In my opinion to use <mo>d</mo> instead of the entity because last is not rendering adequately sound "a bit" tricky and I would discourage that usage. I believe one would be consistent with w3c emphasis of last decade on eliminate tricky visual rendering -e.g. in XHTML-. But more interesting still ;-) is next fragment I also obtained from the MathML 2.0 specification and that has been unnoticed here apparently. <blockquote> 2.3.3 Mixed Markup Examples [...] <mrow> <semantics> <mrow> <msubsup> <mo>∫</mo> <mn>1</mn> <mi>t</mi> </msubsup> <mfrac> <mrow> <mo>ⅆ</mo> <mi>x</mi> </mrow> <mi>x</mi> </mfrac> </mrow> <annotation-xml encoding="MathML-Content"> <apply> <int/> <bvar><ci>x</ci></bvar> <lowlimit><cn>1</cn></lowlimit> <uplimit><ci>t</ci></uplimit> <apply> <divide/> <cn>1</cn> <ci>x</ci> </apply> </apply> </annotation-xml> </semantics> </mrow> [...] In this example, we use the semantics element to provide a MathML content expression to serve as a "semantic annotation" for a presentation expression. In the display markup, we have used the Msubsup element to attach a subscript and a superscript to an expression, in this case the integral sign. We also used entities ∫ and ⅆ to specify the integral and differential symbols. </blockquote> Juan R. Center for CANONICAL |SCIENCE)Received on Monday, 24 April 2006 11:39:00 UTC

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