"Links a metadata graph to the graph for which it specifies the core graph properties including the semantics and the graph namespace. A graph can have only one unique core metadata graph"
"A defining property's value is part of what defines a resource, changing it means
means chaning the identity of the resource. The set of values of all defining
properties of a resource make up its identify.
Whenever comparing resources or sharing them the value of this property should
be taken into account. By default all properties with a literal range are to be
treated as defining properties unless they are marked as nrl:NonDefiningProperty."
"A non-defining property's value is not part of what defines a resource, it rather
is part of the resource's state or expresses an opinion about the resource. Whenever
comparing resources or sharing them the value of this property should not be taken into
account. By default all properties with a resource range are to be treated as
non-defining properties unless they are marked as nrl:DefiningProperty."
