P5: Guidelines for Electronic Text Encoding and Interchange

<rng:element name="charProp">
 <rng:ref name="att.global.attributes"/>
 <rng:ref name="att.typed.attributes"/>
 <rng:group>
  <rng:choice>
   <rng:ref name="unicodeName"/>
   <rng:ref name="localName"/>
  </rng:choice>
  <rng:ref name="value"/>
 </rng:group>
</rng:element>

element charProp
{
   att.global.attributes,
   att.typed.attributes,
   ( ( unicodeName | localName ), value )
}