David Carlisle wrote -- > The original (which I was not on) MathML committee made the decision to > make MathML an XML application. (This was rather lucky as since then XML > has really taken off and become the flavour of the month...) Only in the "real soon now" world; I would say that, even with the mega-bucks behind it, it still needs to be `real-world tested'. I am not trying to knock it but it is not unknown for things like this to fail the reality test despite being excellent concepts and well-implemented. I really wanted to write my assessment of MathML and its relationship to a (vanishingly) small world to everyone but those in it of research mathematics but that deserves a full paper. MathML and Sebastian's ideas of semantic mark-up cater very well for the ideal of what Physicists and Computer Scientists (ie people who designed Mathematica and Maple) think maths and maths notation is. This kind of maths does exist and, from very little knowledge, I believe those physicists who say that they can use, indeed need, a maths notation that is like The Ultimate Programming Language. One where, for example, making a symbol bold has an absolute meaning (like changing `while' to `until' in programming. The kind of maths I indulge in (when not indulging in chat on serious e-mail lists, etc etc:-) is not like this, even at the undergraduate level). It's use of notation and its relation to the semantics are very complex and probably;y not well-understood (they are more like the relationship of natural language to the real world than like the relationship of Pascal to machine code). I know that David is aware of this and that he was addressing other issues. But other contributors have mentioned this complexity and it does have to be addressed. There are other very mundane reasons why some aspects of the MathML-way-of-thinking are good for all users of math notation. One of these is the concept of <mrow>; this is a bad name for something that Don called a `subformula' but which is very badly handled (both syntactically and semantically in `standard TeX/LaTeX'). i shall write more about this some time as it highlights the need to change the way people think whilst not wishing to remove from them their beloved \s (note that I am not so sure about allowing the {}s to remain!). chris