I announced a change to Turtle to allow '-' in names which in particular affects QNames. It was just too handy to not add, plus some existing schemas wouldn't be able to be written down in Turtle QNames, even though they could in RDF/XML. The Notation3 compatibility seems moderate since the N3 systems I tried handle it fine.
The summary I gave for changing it:
- '-' is already seen used in common RDF schema names, such as several in the AKT Reference Ontology, vCard in RDF, Wordnet, ICalendar and probably others (I had a look at SchemaWeb)
- It is natural to use this in converting from other formats that use '-' in names such as IETF ones like vCard and iCalendar.
- It matches a commonly seen XML naming convention to use foo:bar-baz as well as foo:barBaz (lots of XML examples, such as XSLT, XQuery, XPath)