Michael Kohlhase (JacU) has led the development effort for content MathML in the Math Working Group at W3C in collaboration with the JEM partners David Carlisle (NAG), Paul Libbrecht (DFKI), James Davenport (Bath), Chris Rowley (OU), and Olga Caprotti (UH). In this effort, the two leading formats for representing the content of mathematical formulae are harmonized and put on a sound semantic basis. As an effect, the XML encoding of OpenMath3 and the core of content MathML3 (strict content MathML3) will be simple syntactic variants. The MathML2-style encoding of mathematical formulae will be retained as "pragmatic content MathML" and has been given a sound semantic foundation by interpreting it in terms of strict content MathML and via that as OpenMath objects (the then single ontology of mathematical formulae).

In 2008, the harmonization effort concentrates on the MathML3/OpenMath3 standard Content Dictionaries (CDs). CDs are structured XML documents that declare mathematical symbols and concepts and specify their meaning. The form an important representation of mathematical context and allow to disambiguate concepts in mathematical formulae. The concept of CDs was developed in Openmath introduced into MathML3. The specification of the more than 100 MathML2 symbols and concepts of the K-14 math that was part of the MathML2 specification can now be externalized as Content Dictionaries, making the content MathML3 format much more lightweight and flexible. The necessary harmonization of CDs well under way and is expected to be complete in early 2009. JacU and DFKI have established a SVN repository, a CD developers mailing list, and an issue tracker to help organize the effort. The Material from OpenMath2 and MathML2 has been consolidated and merged there; most architectural problems have been addressed, and the ensuing CDs are under editorial review by the group listed above.