The MathML and equation domains provide general containers for equations (inline, block, and display) and an integration with the MathML standard. The equation containers identify equations separate from the data that provides the equation content, which might take many forms, including MathML markup, images, and non-XML formats like TeX and ASCII equations.

These two domains provide support for mathematics elements:

- MathML domain
- Provides the mathml element, which is a specialization of foreign. The mathml element can contain direct MathML markup, or it can use the mathmlref element to include MathML markup that is stored in a separate, non-DITA document. When this domain is integrated without additional constraints, the mathml element is allowed wherever foreign is allowed.
- Equation domain
- Provides the equation-inline, equation-block, and equation-figure elements. This domain can be used independently of the MathML domain. The elements in the equation domain enable authors to clearly distinguish equations from other type of content; these markup distinctions can enable formatting distinctions, numbering of equations, and more.