John Cowan wrote:
> 9) RNG is closed under union and intersection: given two document classes
> described by RNG schemas, one can mechanically construct an RNG schema
> which describes documents appearing in both classes, and another which
> describes documents appearing in either class.
Did we lose set difference? The thing that knocked me out years ago
when Murata started talking about set operations on hedge automata was
the result of Schema A - Schema B. Here's the application: you rev a
schema, then take the difference of version N - version N+1, and get a
schema for the class of documents you've just broken. -Tim
