Arabic mathematical notation
The Math IG just published this Note which analyzes potential problems with the use of MathML for the presentation of mathematics in the notations customarily used with Arabic, and related languages. The goal is to clarify avoidable implementation details that hinder such presentation, as well as to uncover genuine limitations in the specification. These limitations in the MathML specification may require extensions in future versions of the specification.
The XHTML+MathML version displays the examples better, if your user agent supports it.