MathML domain elements
For MathML markup that is stored directly in DITA documents that are validated using DTDs, the MathML elements must use a namespace prefix in order to avoid conflict with the DITA-defined elements of the same name. Documents validated using XSD or RELAX NG can default the MathML namespace on the MathML <math> element. MathML elements that are referenced using the <mathmlref> element do not need to have a namespace prefix, because they are parsed separately from the DITA documents that refer to them. By default, the MathML domain is configured to use the namespace prefix "m" for the MathML elements.