MinimalRdf

What are the useful minimal parts of RDF and XML?

Minimal useful XML

1. Unicode
2. XML declaration - content encoding(*) minimally, utf-8 suffices and doesn't need to be declared.
3. (numeric?) character entities these are redundant, no?
4. element names
5. attribute names and values
6. element content (PCDATA)
7. namespaces minimally, not needed but may be modern XML good practice

Minimal useful RDF

1. Triple
2. URI
3. Unicode string literal (see also TextValues)
4. blank node identifier

Minimal useful RDF/XML

1. rdf:RDF(*)
2. node element and rdf:about/rdf:nodeID
3. property element and rdf:resource/rdf:nodeID
4. literal content

(*)optional

This ignores describing languages, such as by xml:lang in XML.