Implementors of RDF are encouraged to avoid further incompatibility and use the XML convention for system identifiers. In actual practice, the order is significant. A set of values does not allow to model this behaviour. If not, it should be introduced. If there are two ways to express the same thing, but there are slight differences in the expressibility, automatic conversion may not be possible.
Utmost care is necessary to avoid differences.
Parts of the considerations in this item should also be incorporated into Appendix D. - App. First, character encoding is highly relevant for any kind of processing, not only for display. Second, the term 'character set' is misleading. Using 'character encoding' will lead to less confusion.