Yes, XML and RDF use unique namespaces, both using URIs. You can even convert a OID to a URI or a UUID to a URI (both using the "urn:" scheme), so if the format

Yes, XML and RDF use unique namespaces, both using URIs. You can even convert a OID to a URI or a UUID to a URI (both using the "urn:" scheme), so if the format requires a URI as a unique identifier, you can still use a OID or UUID instead if you want to do. (You can also convert a UUID to a OID and then the resulting OID to a URI, which isn't normally helpful because the resulting URI is different from the one directly from the UUID.)