RDF/XML Fini, and Python - slide "Abbreviating URIs"

URIs are long, hard to type, hard to read, and ubiquitous in RDF
There are four ways to abbreviate URIs in RDF/XML:
1. With QNames on elements and attributes (property elements and attributes [REQUIRED] and typed nodes elements)
2. With relative URIs in rdf:about, rdf:resource, and (less often) rdf:datatype
3. With entites in rdf:about, rdf:resource, and rdf:datatype
4. With rdf:ID (though, there is an additional integrity constraint)

rdf:about vs. rdf:ID

rdf:about is analogous to <a href="..."/> in HTML
rdf:ID is analogous to <a name="..."/> in HTML

The rule of thumb is define with rdf:ID (no #), refer with rdf:about (or rdf:resource) with a #, e.g.,:

<rdf:Description rdf:ID="Fluffy">
	<rdf:type rdf:resource="#Cat"/>
	<!--Assuming the current base + '#Cat' is a class-->
<rdf:Descriptoin>
<rdf:Description rdf:about="#Fluffy">
	<thisDoc:loves rdf:resource="#String"/>
</rdf:Description>

RDF has some idyosyncratic relative URI resolution rules
Some style tips:
- Always define a top level xml:base
- Avoid nested xml:bases
- Always use the &xsd; entity for datatypes
- For complex, multi-namespaced documents, entities can help, but you are likely to be confusing at that point no matter what
- Avoid default namespaces, i.e., xmlns=""
- Avoid funky relative URIs (e.g., ../.., etc.)