The RTF specification includes a thorough discussion of the Office 2007 math format. The format syntax is naturally RTF syntax, but the relationship to OMML (Office MathML) is straightforward, as discussed in the specification and in an earlier blog post. Reading the math section of the RTF specification is a great way to learn about the Office math model.
It’s fairly easy to read and write math RTF, so it provides an alternative, potentially easier way to interchange technical documents with Word 2007, especially if the target application already supports an earlier version of RTF.
If you have improvements you’d like to see incorporated into the RTF specification, please send them to me.