The OWL 2 Full semantics of import directives.
I changed the original definition of import closures, as given in the OWL 1 Full spec, by removing two technical aspects: (a) that an imported RDF graph needs to be the "result of the RDF processing of an RDF/XML document", and (b) that such an RDF/XML document needs to be "accessible" at the URI u, which is the RHS of an owl:imports triple. The refined version of this definition now focuses on what it means for a collection of RDF graphs to be an import closure, instead of talking about how to retrieve the different graphs from their containing documents. A change of this form has briefly been discussed at F2F3.
Here is the new formulation:
Let K be a collection of RDF graphs.
K is imports closed
if and only if
for every triple in any element of K of the form
x owl:imports u .
then K contains a graph
that is referred to by u.
The imports closure of a collection of RDF graphs
is the smallest import-closed collection of RDF graphs
containing the graphs.