(topic mathml-d) The MathML reference (<mathmlref>) element is used to refer to a non-DITA XML document containing MathML markup in order to use the markup by reference. The reference must be to a MathML <math> element. The reference may be a URI that addresses an XML document whose root element is a MathML <math> element or a URI that addresses and XML document and a fragment identifier that is the XML ID of a <math> element within the document. NOTE: To reuse MathML markup stored within a DITA topic, use a normal content reference from the <mathml> element. The reference may be direct, via the @href attribute, or indirect, via the @keyref attribute. For key references, only the key name should be specified. Any fragment identifier for specifying the ID of the <mathml> element to use must be specified as part of the key definition's @href value. Example: For example, to refer to the <math> element with the @id value "equation-02" within a larger document using a key reference, you would define the key like so: <keydef keys="mathml-equation-02" href="math/mathml-equations.xml#equation-02" format="mathml"/> You would refer to this key using just the key name: <mathml> <mathmlref keyref="mathml-equation-02"/> </mathml> The MathML should be processed and rendered as though the <m:math> element had occurred directly in the content of the containing <mathml> element. This element is part of the DITA MathML domain. Category: XRef elements The MathML container (<mathml>) element contains inline MathML markup or references to MathML elements stored in a separate non-DITA XML document. The purpose of this element is simply to contain MathML markup. It is not intended, by itself, to convey the semantic of "equation". Rather, it simply serves to hold one of many possible ways that the content of an equation may be represented. The companion equation domain provides elements for representing equations semantically, independent of the format of the equation content. The MathML markup must have a root element of "math" within the MathML namespace "http://www.w3.org/1998/Math/MathML". This element is part of the DITA MathML domain. Category: Foreign elements