From: Stan Devitt <jsdevitt@stratumtek.com>

Date: Sun, 23 Apr 2006 02:12:05 +0200

Message-ID: <ce9128ae0604221712u4828d44bva7adeb9e59a20483@mail.gmail.com>

To: "Stephan.Semirat@ac-grenoble.fr" <Stephan.Semirat@ac-grenoble.fr>

Cc: "David Carlisle" <davidc@nag.co.uk>, www-math@w3.org

Date: Sun, 23 Apr 2006 02:12:05 +0200

Message-ID: <ce9128ae0604221712u4828d44bva7adeb9e59a20483@mail.gmail.com>

To: "Stephan.Semirat@ac-grenoble.fr" <Stephan.Semirat@ac-grenoble.fr>

Cc: "David Carlisle" <davidc@nag.co.uk>, www-math@w3.org

This discussion touches on some very important issues. Presentation MathML is to a large extent about providing information needed to support the visual / aural rendering of a mathematical expression. The "information" that must be provided for rendering includes: - choice of characters. - grouping. (mrow) - relative positioning of the groups. (superscripting / over/ under etc.) It is very much like a printer driver language. If you assume a 1-1 mapping from mathematical expressions to presentations you can read the code generated for the printer. That is, if you are extremely disciplined (as in generating the renderings by machine) about how you construct your presentations using these tools then by mapping selected characters to one particular mathematical meaning and inferring specific functional relationships from the grouping and positioning you can read the markup back in and reconstruct the original mathematical expression. The ⁢ was introduced to make this kind of reverse engineering easier. However, in general this 1-1 mapping (expression to rendering) assumption fails in for two reasons: 1. Different (mathematical) cultures render the same mathematical concept in different ways. 2. Different mathematical disciplines re-use the same characters and notations in different ways. This is true right down at the character level. All you really know about the &differentialD; is that it is just a character that has a recognizable appearance taking into account choice of fonts, etc. Its actual meaning still depends on the mathematical context in which it is being used and is far from being specified by (say) Unicode. Once you have chosen to use &differentialD; you have already decided how you want it to appear. The particular layout has already been chosen, including the characters, once you use Presentation MathML Of course, you can reverse engineer the presentation under the right assumptions and then map it to a different presentation, but the right place to decide this is at the point where you decide to map a mathematical expression to a particular presentation - not afterwards. And one of the roles of Content MathMl is to provide a way to capture the mathematical expression in this presentation independent way. Stan Devitt On 4/20/06, Stephan.Semirat@ac-grenoble.fr <Stephan.Semirat@ac-grenoble.fr> wrote: > > > Hi, > > > > i'd like to know if there's a way to change the default rendering of > > > mathml entities (e.g. rendering ⅆ as a roman d instead > > > of a blackboard d) under FireFox and IE+MathPlayer. > > > > Possibly it's possible to set up the font choices to select a font > > witha d rather than a d| but I tend to do it a simpler way, just > > use d in the source file. Thw blackboard bold operators are there if you > > want to use them but there is no obligation to use them if you don't > want to, > > you can use whatever name you want for any operator. > > Thank you. Is that what you mean : ⅆ and d are just > characters with no "content" meaning ? > > However, if for instance i want to translate my xhtml+mathml files to tex, > then &DifferentialD will be translated to \dd while d will be translated to > d. > So i need to encode these two letter differently, no ? > > (i could also use roman mstyle for d,e,i instead of DifferentialD, > exponentialE, imaginaryI but in fact, these entities are usefull and > meaningfull (to the end user i am) ; it's just that their rendering is not > very conventionnal...) > > Regards, > Stéphan > >Received on Sunday, 23 April 2006 00:12:17 GMT

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