Added a Note about Subtyping to PROV-XML.
--- a/xml/prov-xml.html Mon Nov 19 18:53:44 2012 +0000
+++ b/xml/prov-xml.html Mon Nov 19 14:46:07 2012 -0500
@@ -323,6 +323,46 @@
</p>
</div>
+<div class="note">
+<p>REVIEW QUESTION:</p>
+
+<p>The current design has mirrored the naming from PROV-N. This often
+involves reliance on the "prov:type" attribute to distinguish some
+relations. In order to simplify the overall expression of those
+concepts in XML, we are considering adding additional explicitly named
+top level elements rather than requiring "prov:type".
+</p>
+
+<p>For example, a Quotation is currently expressed in PROV-N as a type
+of Derivation like this:</p>
+<div class="codeexample">
+wasDerivedFrom(a, b, [prov:type='prov:Quotation'])
+</div>
+
+<p>which is transformed to:</p>
+
+<div class="codeexample">
+<prov:wasDerivedFrom><br/>
+ <prov:generatedEntity prov:ref="a"/><br/>
+ <prov:usedEntity prov:ref="b"/><br/>
+ <prov:type xsi:type="xsd:QName">prov:Quotation</prov:type><br/>
+</prov:wasDerivedFrom>
+</div>
+
+<p>This proposal would replace that with an explicit "Quotation" element:
+</p>
+
+<div class="codeexample">
+<prov:Quotation><br/>
+ <prov:generatedEntity prov:ref="a"/><br/>
+ <prov:usedEntity prov:ref="b"/><br/>
+</prov:Quotation>
+</div>
+
+<p>Other "typed" concepts and relations would be handled similarly.
+</p>
+
+</div>
</section>