The XML standard allows for namespace domains, in which element names belong to either the empty (null) namespace or to a namespace that belongs to a particular XML grammar. Namespaces are identified by a uniform resource identifier (URI) that is fashioned, similar to a URL, in order that uniqueness is guaranteed.

The DAVE-ML namespace should be defined in the top-level element as follows:

          <DAVEfunc xmlns="http://daveml.org/2010/DAVEML">
	  

This will allow DAVE-ML models to be embedded in other XML documents without confusion. Note that this general URI is not a URL; HTTP queries at that address may not lead to any useful information.

The reference element can include two elements that belong to the World-Wide Web Consortium (W3C)'s XLINK protocol [W3C-XLINK]; they are defined with an xlink: prefix which actually refers to the namespace uniquely defined with the http://www.w3c.org/1999/xlink URI. If external links to documents will be included in a DAVE-ML document, the top-level element (currently reference) must include a namespace declaration (which looks like, but technically is not, an attribute):

          <reference xmlns:xlink="http://www.w3.org/1999/xlink">
          

Similarly, the MathML-2 elements are normally defined in a MathML namespace, so any calculation defined using MathML-2 notation should be conducted inside the MathML namespace:

          <math xmlns="http://www.w3.org/1998/Math/MathML">