# MathML

Yelp supports MathML in both Mallard and Doc`Book documents. In both cases, you can use MathML both inline and as a block element. In Mallard, you can use Mallard's internal linking mechanism on MathML elements. `

Yelp uses the MathJax library to support MathML in all modern browsers and browser engines. The default output of the Yelp XSLT uses `cdn.mathjax.org`. The Yelp viewer bundles a subset of MathJax, allowing it to display MathML in its embedded WebKit viewer without using the network.

## Mallard

To add MathML to a Mallard document, use an `mml:math` element in any block or inline context. Yelp automatically sets the `display` attribute of the output `mml:math` element according to context, even overriding any source value.

You can use the namespaced mal:xref attribute on any MathML element to link to another page in the same document.

Added in 3.8.

## DocBook

To add MathML to a Doc`Book document, use an ``mml:math` element inside an `equation` element (4 or 5), `informalequation` element (4 or 5), or `inlineequation` element (4 or 5). Or, in Doc`Book 5 only, use an ``mml:math` element inside an imagedata element with the `format` attribute set to `"mathml"`.

An `mml:math` element is considered a block element if it occurs in an `equation` or `informalequation` element, or if it occurs in an `imageobject` element in a `mediaobject` element. An `mml:math` element is considered inline if it occurs in an `inlineequation` element, or if it occurs in an `imageobject` element in an `inlinemediaobject` element. Yelp automatically sets the `display` attribute of the output `mml:math` element accordingly, even overriding any source value.

Added in 3.8.