--- a/rdf-concepts/index.html	Thu Jun 27 13:55:18 2013 -0600
+++ b/rdf-concepts/index.html	Thu Jun 27 14:42:53 2013 -0700
@@ -792,6 +792,10 @@
     implementations do not track empty <a title="named graph">named graphs</a>.
     Applications can avoid interoperability issues by not
     ascribing importance to the presence or absence of empty named graphs.</p>
+
+    <p>Blank nodes as graph names are new.  Existing SPARQL implementations
+      might not accept this new feature for some time, so 
+  the use of blank nodes as graph names can cause interoperability problems.</p>
     </div>
 
 <section id="section-dataset-isomorphism">
@@ -1280,6 +1284,25 @@
     representations of the same primary resource.</p>
 </section>
 
+<section id="section-generalized-rdf" class="informative">
+    <h2>Generalized RDF Triples, Graphs, and Datasets</h2>
+
+<p>It is sometimes convenient to loosen the requirements on <a>RDF
+    triple</a>s.  For example, the completeness of the RDFS entailment rules
+    is easier to show with a generalization of RDF triples.  Note that any
+    users of these generalized notions need to be aware that their use may
+    cause interoperability problems, and that there is no requirement on the
+    part of any RDF tool to accept, process, or produce anything beyond
+    regular RDF triples, graphs, and datasets. </p>
+
+    <p><em>A generalized RDF triple</em> is an RDF triple generalized so
+    that subjects, predicates, and objects all allowed to be IRIs, blank
+    nodes, or literals.  A <em>generalized RDF graph</em> is an RDF graph of
+    generalized RDF triples, i.e., a set of generalized RDF triples.
+    A <em>generalized RDF dataset</em> is an RDF dataset of generalized RDF
+    graphs where graph labels can be IRIs, blank nodes, or literals.</p>
+
+</section>
 
 <section id="section-Acknowledgments" class="informative">
     <h2>Acknowledgments</h2>