Okay, here's my first crack at rules for showing the contradiction Alan mentioned, i.e., that <http://sw-app.org/mic.xhtml#i> is both a foaf:Person and an html:DocumentPortion.  BTW, if the lines below get garbled in email, then it may be easier to read the attachment.

Let's assume an app has a triple:

	_:foo dc:creator <http://sw-app.org/mic.xhtml#i> . 

And we'll assume that in parsing the above triple, the app *also* automatically asserted the following triple, in order to remember what URI was used to denote the resource:

	<http://sw-app.org/mic.xhtml#i> log:uri
		"http://sw-app.org/mic.xhtml#i"^^xsd:anyURI . 

Now suppose that the app somehow decides that it wants to learn more about the resource denoted by http://sw-app.org/mic.xhtml#i .  To do so, it uses a few rules.  The first rule extracts the RDF and HTML (separately) from the RDFa:

# See prefix declarations at the end of this message.
{	?r log:uri ?u .				# IF a resource is denoted by URI ?u
	?u log:racine ?racine .			# ... which has racine ?racine
	?racine mhttp:hasResponse ?reply .	# ... and a GET yields response ?reply
	?reply http:status "200" .		# ... which was 200 OKAY
	?reply mime:body ?body .		# ... and it has body ?body
	?reply mime:content-type "rdfa" .	# ... which is mime type RDFa
	?body rdfa:parsedAsRDFA ?rdfa .	# ... which parses to RDFa ?rdfa
} => {						# THEN
	?u mhttp:yields ?f .			# ... dereferencing ?u yields ?f
	?f a log:Formula .			# ... which is RDF
	?u mhttp:yields ?h .			# ... and dereferencing ?u yields ?h
	?h a html:HTML .				# ... which is HTML
	}

The second rule is specific to the RDF mime type.  It says that RDF that comes back is asserted.

{	?u mhttp:yields ?f .			# IF dereferencing ?u yields ?f
	?f a log:Formula .			# ... which is RDF
} => ?f .						# THEN assert it.

And according to Alan's message at
http://lists.w3.org/Archives/Public/public-awwsw/2007Dec/0011.html
the RDFa at http://sw-app.org/mic.xhtml contains embedded RDF that explicitly asserts:

	<http://sw-app.org/mic.xhtml#i> a foaf:Person .

or something to that effect.  I didn't check, but I'll take that as a given.

The third rule is specific to HTML mime types.  It indicates that in HTML, a fragment identifier denotes a portion of a document (or a location within a document):

{	?u log:racine ?u .			# IF ?u is already a racine (no frag ID)
	?u mhttp:yields ?h .			# ... and dereferencing it yields ?h
	?h a html:HTML .				# ... which is HTML
	?h html:containsID ?id .		# ... and it contains ID ?id
	(?u "#" ?id) string:concatenation ?uid . # ... and the URI ?u#?id
	?rid log:uri ?uid .			# ... denotes a resource ?rid
} =>	{						# THEN
	?rid a html:DocumentPortion .		# ... it is a document portion.
	}

Alan's message also says that the RDFa at http://sw-app.org/mic.xhtml contains id:"i", which by the third rule means:

	<http://sw-app.org/mic.xhtml#i> a html:DocumentPortion .

And AWWW seems to suggest the people are no document portions:

	html:DocumentPortion owl:disjointWith foaf:Person .

and so we have a contradiction.

The above rules assume the following prefixes:

	@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
	@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
	@prefix log: <http://www.w3.org/2000/10/swap/log#>.
	# HTTP ontology mentioned by Jonathan:
	@prefix http: <http://www.w3.org/2007/ont/http#> .

	# Ontology for more about HTTP:
	@prefix mhttp: <http://example/more-http> .
	mhttp:hasResponse a rdf:Property ; 
		rdfs:domain xsd:anyURI ; 
		rdfs:range http:ResponseMessage .
	mhttp:ParsedBody a rdf:Property .	# Any result of parsing a MIME body
	mhttp:yields a rdf:Property ;		# What dereferencing a URI yields
		rdfs:domain xsd:anyURI ;
		rdfs:range ParsedMimeBody .

	# Ontology for interpreting RDFa:
	@prefix rdfa: <http://example/mime-type-rdfa> .
	rdfs:RDFA a rdfs:Class .		# RDFa documents
	rdfa:parsedAsRDFa a rdf:Property ;	# Analogous to log:parsedAsN3
		rdfs:domain mime:Body ;
		rdfs:range rdfa:RDFa .
	rdfa:containsRDF a rdf:Property ;
		rdfs:domain rdfa:RDFa ;
		rdfs:range log:Formula .
	rdfa:containsHTML a rdf:Property ;
		rdfs:domain rdfa:RDFa ;
		rdfs:range html:HTML .

	# Ontology for interpreting HTML:
	@prefix html: <http://example/mime-type-html> .
	html:HTML a rdfs:Class ;		# HTML documents
		rdfs:subClassOf mhttp:ParsedBody .
	html:parsedAsHTML a rdf:Property ;	# (Not used in this example)
		rdfs:domain mime:Body ;		# (Not used in this example)
		rdfs:range html:HTML .		# (Not used in this example)	
	html:containsID a rdf:Property ;
		rdfs:domain html:HTML ;
		rdfs:range xsd:string .
	html:DocumentPortion a rdfs:Class .	# Location denoted by a frag ID.



David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Opinions expressed herein are those of the author and do not represent the official views of HP unless explicitly stated otherwise.