DTD and a label for the namespace identifier. If in contract, I must cite the record of authority for the defined item, I require it to be a singleton. No Bifurcation at Root. Sorry, mad'm, if the thread avoided your question.
Locations are points in space or time.
Locations bound to names enable persistence and uniqueness. Identities bound into a namespace. Systems to bind identities 6. The source is the collection of instances, or documentation of instances to be transformed to the target namespace. Create a table where the names in the source definition are mapped to the target.