Are subject schemes global?

George Bina and Radu Coravu from oXygen brought the attention of the DITA-OT project members (Robert, Eliot, me, Eric Sirois) to the following sentence (emphasis added) in the DITA 1.2 spec: Subject scheme maps use key definition to define a collection of controlled values rather than a collection of topics.
The highest level of map that uses the set of controlled values must reference the subject scheme map in which those controlled values are defined.
We've already agreed to to remove the must in the second sentence, to make it possible for a processor to set the subjectScheme map at the command line; I think it probably would also be wise to clarify that subjectScheme maps are intended to create a global subjectScheme space for a publication.
In general, I think we should make handling of subjectScheme as parallel as possible to how we handle keys.
So I'd also suggest that for enumerations, the highest value is effective.

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Best, Kris Kristen James Eberlein Principal consultant, Eberlein Consulting Co-chair, OASIS DITA Technical Committee Charter member, OASIS DITA Adoption Committee www.eberleinconsulting.com +1 919 682-2290; kriseberlein (skype)