[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: RE: [xdi] Re: XDI subjects (was Groups - XDI RDF v8 Comments-Barnhill)
Kermit,
I agree with the logic of your conclusion that for the same reasons as RDF, XDI RDF should not allow literals to be subjects.
However when you say, "if only objects may be literals, then it's impossible to have reflexive predicates...", that overlooks that RDF objects may be:
* literals
* URIs
* blank nodes
I believe your statement is correct that reflexive predicates do not make sense when the object is a literal. However they make perfect sense when the object is a URI -- or in the case of XDI RDF, an XRI.
That's why I've always thought of $is as the "synonym predicate" -- in XDI RDF, it asserts that two XRIs -- the subject XRI and the object XRI -- are synonyms, i.e., they are XRIs that identify the same resource.
I think the same thing applies to all of the atomic relations ($a, $is, $has, etc.) in the XDI RDF Model document (http://wiki.oasis-open.org/xdi/XdiRdfModel), i.e., all of them ONLY express relations between two XDI resources -- a subject resource and an object resource -- and therefore the object of any of these predicates MUST be an XRI and not a literal.
(I don't know yet about whether their object can be an XDI subcontext -- our equivalent of an RDF blank node -- I need to think on that).
=Drummond
> -----Original Message-----
> From: kermit.snelson@gmail.com [mailto:kermit.snelson@gmail.com] On Behalf
> Of Kermit Snelson
> Sent: Wednesday, March 19, 2008 7:52 PM
> To: Drummond Reed
> Cc: Giovanni Bartolomeo; Markus Sabadello; barnhill_william@bah.com;
> xdi@lists.oasis-open.org
> Subject: Re: [xdi] Re: XDI subjects (was Groups - XDI RDF v8 Comments-
> Barnhill)
>
> These issues are indeed very difficult to discuss over email, so I'm
> all for deferring them to tomorrow's telecon.
>
> But in the meantime, I do have an easy-to-express-over-email thought about
> this:
>
> > Also, the reflexive properties of "is" would seem to hold across any
> combination
> > of the subjects and objects of these statements
>
> I'm not yet convinced that does work, actually, even in English. The
> reasoning here:
>
> The number of beers in a case is 24.
> 24 is the number of hours in a day.
> Therefore, the number of beers in a case is the number of hours in a
> day.
>
> is really no better than this:
>
> Sushi is better than nothing.
> Nothing is better than sex.
> Therefore, sushi is better than sex.
>
> The problem with the first syllogism (and it's probably already
> obvious that "nothing" is wrong with the second one) is its
> implication that changing the number of beers in a standard case to be
> 16 would also require changing the number of hours in a day to be 16,
> which probably isn't true.
>
> My point here is that using literals both as subjects and as objects
> can cause problems even in English, and I suspect that's one of the
> reasons why RDF, which is designed to express semantics with
> sufficient precision that even machines can't get confused, allows
> only objects to be literals. And if only objects may be literals, then
> it's impossible to have reflexive predicates, because otherwise
>
> <http://example.com/number/of/beers/in/a/case> <$is> <"24">.
>
> would imply
>
> <"24"> <$is> <http://example.com/number/of/beers/in/a/case>.
>
> =Kermit
>
> On 3/19/08, Drummond Reed <drummond.reed@cordance.net> wrote:
> > To me, this is a wonderful example (or painful example, depending on
> your view) of how some aspects of this subject are going to be difficult
> to discuss via such a low-bandwidth medium (or at least a slow-bandwidth
> medium) as email.
> >
> > To be specific, I think I understand the point Giovanni is making, and
> the one Kermit is making. However, I think that if we are very precise
> (which we're going to have to be in XDI RDF), they actually illustrated
> why $is is reflexive.
> >
> > I'll try to quickly explain what I mean while providing the caveat that
> this may be going to be hard to discuss in email, and thus I suggest we
> take it up further on tomorrow's telecon (to which I'll add it to the
> agenda, coming out next).
> >
> > I'm going to assume that Kermit's example of using the predicate
> "http://english.com/is"; is a clever way of saying, "the predicate known in
> English language as the word 'is'". (If I was wrong about that, Kermit,
> let me know).
> >
> > If so, then in "English pseudo-X3", you could say what Kermit was
> expressing as:
> >
> > The number of hours in a day
> > is
> > 24.
> > The number of beers in a case
> > is
> > 24.
> >
> > If so, the inverse of both these statements would appear to be valid:
> >
> > 24
> > is
> > the number of hours in a day.
> > 24
> > is
> > the number of beers in a case.
> >
> > Also, the reflexive properties of "is" would seem to hold across any
> combination of the subjects and objects of these statements, i.e., you
> could say:
> >
> > 24
> > is
> > 24
> > The number of hours in a day
> > is
> > the number of beers in a case.
> > The number of beers in a case
> > is
> > the number of hours in a day.
> >
> > So if we agree that in all these statements the subject is a number and
> the object is a number -- just described in different ways -- then I think
> everything works. BUT if Kermit's point was that the literal "24" as a
> subject cannot be intrinsically determined to be a number, then I agree
> that there may be issues about making statements about a literal as a
> subject.
> >
> > Given that, here's a challenge. What about the following set of XDI
> statements (moving to formal X3 Whitespace for clarity):
> >
> > ["24"
> > [$is$a
> > [$literal]
> > [$type$xsd$string]
> > [$type$xsd$integer]
> > ]
> > ]
> >
> > Doesn't all that make sense? (Again, I'm not necessarily advocating for
> XDI subjects to allow literals. I'm just challenging the notion that
> there's anything logically wrong with it. The above all appears pretty
> intuitive to me.)
> >
> >
> > =Drummond
> >
> >
> > > -----Original Message-----
> > > From: kermit.snelson@gmail.com [mailto:kermit.snelson@gmail.com] On
> Behalf
> > > Of Kermit Snelson
> > > Sent: Wednesday, March 19, 2008 12:57 PM
> > > To: Giovanni Bartolomeo
> >
> > > Cc: Drummond Reed; Markus Sabadello; barnhill_william@bah.com;
> > > xdi@lists.oasis-open.org
> >
> > > Subject: Re: [xdi] Re: XDI subjects (was Groups - XDI RDF v8 Comments-
> > > Barnhill)
> > >
> >
> > > That's an excellent point, Giovanni.
> > >
> > > My own conclusion from your observation, however, is that the change
> > > introduced in XDI/RDF V9 that made $is reflexive and therefore
> > > eliminated $a$is as inverse was a mistake and should be repealed.
> > >
> > > The fact that RDF describes a directed graph, together with the fact
> > > that a subject is not the same thing as an object, leads me to
> believe
> > > that it's not meaningful to have reflexive (i.e., bidirectional)
> > > predicates in RDF.
> > >
> > > =Kermit
> > >
> > > On 3/19/08, Giovanni Bartolomeo <giovanni.bartolomeo@uniroma2.it>
> wrote:
> > > > Hello,
> > > >
> > > > I think I've now understood why we cannot have
> > > > XDI documents (and possibly literals) in subjects
> > > > (i.e. to have a full addressable RDF graph).
> > > > However, with predicates like $is and their
> > > > inverse (which is $is) we should proceed
> > > > carefully. Coming back to the third example by
> > > > Kermit, if we use $is as predicate we've exactly what Kermit
> suggested:
> > > >
> > > >
> > > > <"http://example.com/number/of/hours/in/a/day";>
> > > > <"http://english.com/is";> <"24">
> > > > <"http://example.com/number/of/beers/in/a/case";>
> > > > <"http://english.com/is";> <"24">
> > > >
> > > >
> > > > <"24"> <"http://english.com/is";>
> > > > <"http://example.com/number/of/hours/in/a/day";>
> > > > <"24"> <"http://english.com/is";>
> > > > <"http://example.com/number/of/beers/in/a/case";>
> > > >
> > > >
> > > > This is implicit in $is which MUST be symmetric
> > > > ($is inverse predicate is $is). Otherwise, I
> > > > think, the semantics of $is is lost. But probably
> > > > here $is is not the best predicate...
> > > >
> > > > Giovanni
> > > >
> > > >
> > > > At 20.57 18/03/2008, Kermit Snelson wrote:
> > > > >There are at least three reasons, in my opinion,
> > > > >why XDI/RDF subjects can't be literals: 1) RDF
> > > > >itself doesn't allow literals as subjects:
> > > > >http://www.w3.org/TR/rdf-concepts/#dfn-subject
> > > > >2) The proper XDI mapping of: Blah blah <a
> > > > >href="http://example.com/some/target";>some
> > > > >literal text here</a> blah blah would be: XDI
> > > > >subject = "http://example.com/some/target"; XDI
> > > > >predicate = $html$a XDI object = "some literal
> > > > >text here" and the corresponding inline X3, with
> > > > >the additional predicates in Drummond's example,
> > > > >would be something like: Blah blah
> > > > >[http://example.com/some/target[$html$a["some
> > > > >literal text here"]]
> > > >
> > >
> >[$uri$https[https://example.com/resolvable/uri]][$is[@!F83.62B1.44F.2813!
> > > 1234]]
> > > > >blah blah 3) Allowing literals as subjects
> > > > >doesn't make logical sense. Consider the
> > > > >following:
> > > > ><"http://example.com/number/of/hours/in/a/day";>
> > > > ><http://english.com/is";>
> > > > ><"24">.
> > > > ><"http://example.com/number/of/beers/in/a/case";>
> > > > ><http://english.com/is";> <"24">. So far, so
> > > > >good. But to assert the following: <"24">
> > > > ><"http://english.com/is";>
> > > > ><"http://example.com/number/of/hours/in/a/day";>.
> > > > ><"24"> <"http://english.com/is";>
> > > > ><"http://example.com/number/of/beers/in/a/case";>.
> > > > > is to assert some substantial connection
> > > > >between the number of hours in a day and the
> > > > >number of beers in a case, which is fallacious.
> > > > >=Kermit On 3/18/08, Drummond Reed
> > > > ><drummond.reed@cordance.net> wrote: > > > > >
> > > > >First, let me be clear: I'm not a big fan of
> > > > >using literals as subjects, and > I don't have
> > > > >any compelling use cases for it (see below for
> > > > >the only one > I've been thinking about). It was
> > > > >Giovanni who seemed to have a reason for > using
> > > > >literals as subjects. > > > > Second, I agree, a
> > > > >literal as a subject can't be changed or it
> > > > >becomes a new > subject from an XDI
> > > > >standpoint. > > > > Now, here's the one thing
> > > > >that's had me thinking about
> > > > >literals-as-subjects > for a long time take a
> > > > >standard HTML link
> > > > >tag: > > > > Blah blah <a >
> > > > >href="http://example.com/some/target";>some
> > > > >literal text > here</a> blah blah > > > > If you
> > > > >wanted to turn this into an XDI statement, the
> > > > >only logical mapping > that seems to make sense
> > > > >is: > > > > XDI subject = "some
> > > > >literal text here" > > XDI predicate
> > > > >= $uri > > XDI object =
> > > > >"http://example.com/some/target"; > > > > In
> > > > >other words, were you to replace HTML <a> tags
> > > > >with X3 within an HTML > document, the above
> > > > >link would look like: > > > > Blah
> > > > >blah ["some literal text >
> > > > >here"[$uri["http://example.com/some/target";]]]
> > > > >blah blah > > > > That's pretty cool, because
> > > > >now you have a way of embedding really rich >
> > > > >semantics into ordinary web pages and web links.
> > > > >As a simple example, image > being able to make
> > > > >the above simple link into a compound statement,
> > > > >which > includes: a) an alternate HTTPS URL for
> > > > >the target resource, and b) a > persistent XRI
> > > > >synonym for the
> > > > >resource: > > > > Blah blah ["some
> > > > >literal text >
> > > > >here"[$uri["http://example.com/some/target";]] >
> > > >
> > >
> >[$uri$https["https://example.com/some/target"]][$is[@!F83.62B1.44F.2813!1
> > > 234]]
> > > > > > blah blah > > > > Net net: it's the ability
> > > > >to put XDI statements inline in ordinary HTML
> > > > >and > other markup formats that's the strongest
> > > > >use case I've seen so far for > being able to
> > > > >treat literals as XDI subjects. > > > >
> > > > >=Drummond > > > > > > >
> > > > >________________________________ > > > From:
> > > > >markus.sabadello@gmail.com
> > > > >[mailto:markus.sabadello@gmail.com] On > Behalf
> > > > >Of Markus Sabadello > Sent: Tuesday, March 18,
> > > > >2008 9:30 AM > To: Drummond Reed > Cc:
> > > > >Giovanni Bartolomeo; barnhill_william@bah.com;
> > > > >xdi@lists.oasis-open.org > Subject: [xdi] Re:
> > > > >XDI subjects (was Groups - XDI RDF v8
> > > > >Comments-Barnhill) > > > > > > One aspect that
> > > > >seems strange with using literals as subjects is
> > > > >that you > can't modify them with XDI messages
> > > > >(I think). > > If you
> > > > >have > > =drummond > +name >
> > > > >"Drummond" > > You can modify the literal like
> > > > >this: > > =drummond > $mod > / >
> > > > > =drummond > +name >
> > > > > "D.Reed" > > But you can't modify a
> > > > >subject. > > What again was a use case for
> > > > >literals in subjects? (I'm not against it, >
> > > > >just asking) > > Markus > > > On Mon, Mar 17,
> > > > >2008 at 7:34 PM, Drummond Reed
> > > > ><drummond.reed@cordance.net> > wrote: > > > >
> > > > >[renaming this thread to something more
> > > > >relevant] > > > > Giovanni, > > > > I agree with
> > > >
> > > > >Markus I can't make sensee of having an XDI
> > > >
> > > > >document as an XDI > subject. I'm not sure my
> > > > >point from my earlier message came across, but
> > > > >I > was saying that when you use XDI context
> > > > >syntax the // syntax it does > _not_ assert
> > > >
> > > > >that the previous XDDI document is the subject
> > > >
> > > > >of an XDI > statement. It says that the previous
> > > > >XDI statement _contains_ another XDI >
> > > > >statement. For example, in the following X3
> > > >
> > > > >Simple graph… > > > >
> > > >
> > > > >=drummond > > +email > >
> > > > > / > >
> > > > > =drummond > >
> > > > > +email+home > > >
> > > > >"dsr.example@gmail.com" > >
> > > > > +email+work > > >
> > > > >"drummond.example@cordance.net" > > > > …you can
> > > >
> > > > >makke the following "compound XDI
> > > >
> > > > >statement": > > > >
> > > > >=drummond/+email//=drummond/+email+home > > > >
> > > > >This compound statement does not assert an XDI
> > > > >document as a subject. It > asserts the
> > > > >following: > > > > 1) =drummond is an XDI
> > > > >subject > > 2) +email is an XDI predicate of
> > > > >this subject > > 3) The object is another XDI
> > > > >document > > 4) =drummond is an XDI subject in
> > > > >this contained XDI document > > 5) +email+home
> > > > >is an XDI predicate of that XDI subject > > 6)
> > > > >"dsr.example@gmail.com" is the literal value of
> > > > >that XDI object > > > > If you wanted to have an
> > > > >entire XDI document as the subject of an XDI >
> > > > >statement, I think the syntax you are looking
> > > > >for is: > > > > >
> > > > >(xdi-subject/$context$xdi)/xdi-predicate/xdi-object
> > > > > > > > > In this XDI statement: > > > > 1)
> > > > >(xdi-subject/$context$xdi) is a cross reference
> > > > >that uniquely identifies > an XDI
> > > > >document: > > a) xdi-subject is the
> > > > >XDI subject authoritative for a reference > to
> > > > >the XDI document > > b) $context$xdi
> > > > >is the context type > > 2) xdi-predicate is the
> > > > >XDI predicate whose subject is the entire
> > > > >previous > cross-reference > > 3) xdi-object is
> > > > >whatever the XDI object is (literal, another XDI
> > > > >subject, > or another XDI document) > > > >
> > > > >**************** > > > > As for the issue of
> > > > >whether a literal can be an XDI subject, my
> > > > >primary > concern about that is how to treat it
> > > > >under XDI addressing rules. In every > XDI
> > > > >context, the XRIs must be unique. So there are
> > > > >two directions we could > take: > > > > 1) Allow
> > > > >literals to be XDI subjects, but ignore them
> > > > >from an XDI addressing > perspective (i.e., they
> > > > >would be "invisible" from an addressing
> > > > >standpoint.) > > > > 2) Allow literals as XDI
> > > > >subjects in syntax, but for addressing
> > > > >purposes, > have a specified transformation into
> > > > >relative XRI. For example: > > > > ["Drummond
> > > > >Reed"[+email[""dsr.example@gmail.com"]]] <==X3
> > > > >with literal as > non-addressable subject > >
> > > > >[%44rummond%20%52eed[+email[""dsr.example@gmail.com"]]]
> > > > ><==X3 with literal > as addressable XRI
> > > > >subject > > > > Thoughts? > > > >
> > > > >=Drummond > > > > > > >
> > > > >________________________________ > > > From:
> > > > >markus.sabadello@gmail.com
> > > > >[mailto:markus.sabadello@gmail.com] On > Behalf
> > > > >Of Markus Sabadello > Sent: Monday, March 17,
> > > > >2008 9:10 AM > To: Giovanni Bartolomeo > Cc:
> > > > >Drummond Reed; barnhill_william@bah.com;
> > > > >xdi@lists.oasis-open.org > Subject: Re: [xdi]
> > > > >Groups - XDI RDF v8 Comments-Barnhill (pdf) (XDI
> > > > >RDF v8 > Comments-Barnhill.pdf)
> > > > >uploaded > > > > > From the standpoint of
> > > > >having already implemented this, the proposal
> > > > >of > allowing a subject to be an XDI document
> > > > >(aka subcontext aka inner graph) is > a
> > > > >nightmare.. > > I can think of at least the
> > > > >following immediate problems: > - Some of the
> > > > >serialization formats may not be able to express
> > > > >this. > - We always said that subjects in a
> > > > >graph must be unique. Can this still be >
> > > > >enforced with inner graphs as subjects? > -
> > > > >What will XDI messages look like that make
> > > > >changes to these subjects? > > I don't feel too
> > > > >secure about allowing literals as subjects
> > > > >either, but I > can't really argue why at this
> > > > >point.. > > But I'm just thinking loud.. Of
> > > > >course all this is not necessarily a reason >
> > > > >not to do it :) > > Markus > > > On Sat, Mar
> > > > >15, 2008 at 1:39 PM, Giovanni Bartolomeo >
> > > > ><giovanni.bartolomeo@uniroma2.it> wrote: > > > >
> > > > >At 20.52 13/03/2008, Drummond Reed wrote: > >
> > > > >Giovanni, > > It's a subtle point, but when you
> > > > >use subcontext syntax (//), the parent > XDI
> > > > >document is not the subject of the child XDI
> > > > >document. It is the > container ("context") for
> > > > >the child. Thus I don't think the ABNF should >
> > > > >change. > > > > > Ok, I see; so if my
> > > > >understanding is correct, we have both the
> > > > >possibility > to have a whole XDI document as an
> > > > >RDF object as well as a "contained" > object
> > > > >("subcontext"). Thus, the original question: in
> > > > >these ABNF excerpts, > how could we specify that
> > > > >a subject can be an XDI document?
> > > > >E.g. > > > > X3 = *( "[" sub *( "[" pred *( "["
> > > > >obj "]" ) "]" ) "]" ) > sub = [ comment ]
> > > > >xri-reference [ comment ] > sub = [ comment ]
> > > > >(xri-reference / X3) [ comment ] > pred = [
> > > > >comment ] xri [ comment ] > obj = [ comment ] (
> > > > >xri-reference / literal / X3 ) [ comment
> > > > >] > literal = """ *char """ > comment = "<--"
> > > > >*c-char "-->" > > > > RE the question of whether
> > > > >to allow a literal as an XDI subject, yes, I
> > > > >have > thought about, for reasons which I'll
> > > > >explain on today's call (if we have >
> > > > >time). > > > > I would allow this; especially if
> > > > >we'll standardize inverse predicates, we >
> > > > >should allow a subject to be a literal, as well
> > > > >as a XDI document or a >
> > > > >xri-reference. > > > > > > > > RE whether a
> > > > >predicate should be able to be an XDI document,
> > > > >my immediate > answer is no RDF predicates are
> > > >
> > > > >strictly URIs; XDI preedicates should be >
> > > >
> > > > >strictly XRIs. > > > > Yes, I agree with this.
> > > > >To summarize, I would be in favour of having
> > > > >the > same definition for subjects and
> > > > >objects: > > sub = [ comment ] (xri-reference /
> > > > >literal / X3) [ comment ] > > > pred = [ comment
> > > > >] xri [ comment ] > obj = [ comment ] (
> > > > >xri-reference / literal / X3 ) [ comment ] > >
> > > > >what do you
> > > > >think? > > Thanks, >
> > > > >Giovanni > > > > > > > > > Talk to you
> > > > >shortly, > > =Drummond > >
> > > > >________________________________ > > > From:
> > > > >Giovanni Bartolomeo [ >
> > > > >mailto:giovanni.bartolomeo@uniroma2.it] > Sent:
> > > > >Thursday, March 13, 2008 3:11 AM > To: Drummond
> > > > >Reed; 'Markus Sabadello' > Cc:
> > > > >barnhill_william@bah.com;
> > > > >xdi@lists.oasis-open.org > Subject: RE: [xdi]
> > > > >Groups - XDI RDF v8 Comments-Barnhill (pdf) (XDI
> > > > >RDF v8 > Comments-Barnhill.pdf)
> > > > >uploaded > > Hello Drummond, > > Thanks for
> > > > >this clarification; however, if my understanding
> > > > >is correct, > this means that an XDI document
> > > > >can also be subject of another XDI document, >
> > > > >other than object. > Doesn't this implies that
> > > > >we should update ABNF syntax making the >
> > > > >definition of subject somehow similar to the one
> > > > >for object? > > X3 = *( "[" sub *( "[" pred *(
> > > > >"[" obj "]" ) "]" ) "]" ) > sub = [ comment ]
> > > > >xri-reference [ comment ] > sub = [ comment ]
> > > > >(xri-reference / X3) [ comment ] > pred = [
> > > > >comment ] xri [ comment ] > obj = [ comment ] (
> > > > >xri-reference / literal / X3 ) [ comment
> > > > >] > literal = """ *char """ > comment = "<--"
> > > > >*c-char "-->" > > Further questions
> > > > >are: > > should allow literals as a
> > > > >subject? > should be predicate
> > > > >definition similar to subject and object one >
> > > > >update, e.g. may a predicate contain an XDI
> > > > >document? > > however I'm not quite convinced
> > > > >with these last two ideas... comments >
> > > > >welcome! > > Giovanni > > > At 22.38
> > > > >12/03/2008, Drummond Reed wrote: > > Just to be
> > > > >clear, the "n-segment" syntax was deprecated in
> > > > >the V9 XDI RDF > Model document ( >
> > > > >http://wiki.oasis-open.org/xdi/XdiRdfModel) due
> > > > >to the > problems identified in this thread. To
> > > > >be precise, it was unclear
> > > > >whether > > s1 > p1 >
> > > > > o1 >
> > > > > p2 >
> > > > > o2 > > meant that s1/p1/o1 was the
> > > > >subject of p2/o2 or not. It was also unclear >
> > > > >how cross-reference syntax would be
> > > > >applied. > > We solved both problems by
> > > > >eliminating "n-segment" syntax in the V9 >
> > > > >document. Now it should be unambiguous that if
> > > > >you want to express that > s1/p1/o1 is the
> > > > >subject of p2/o2, you
> > > > >say: > > (s1/p1/o1)/p2/o2 > > What
> > > > >did remain is the // syntax for subcontexts,
> > > > >which allows you to solve > the RDF "blank node
> > > > >problem" by providing an address for a blank
> > > > >node. That > address is simply // (which fits
> > > > >very nicely from a conceptual standpoint > since
> > > > >the identifier for that segment is
> > > > >"blank"). > > So if I want to say that the
> > > > >object of s1/p1 is a blank node, I can write >
> > > > >it as s1/p1// . This creates a new XDI context
> > > > >in which I can express > another set of XDI
> > > > >statements whose XRIs are unique in this
> > > > >context. > > We'll go over the practical uses
> > > >
> > > > >for this on the call tomorrow aagenda > coming
> > > >
> > > > >out
> > > > >shortly. > > =Drummond > >
> > > > >________________________________ > > > From:
> > > > >markus.sabadello@gmail.com [ >
> > > > >mailto:markus.sabadello@gmail.com] On Behalf Of
> > > > >Markus > Sabadello > Sent: Wednesday, March 12,
> > > > >2008 10:44 AM > To: Giovanni Bartolomeo > Cc:
> > > > >barnhill_william@bah.com;
> > > > >xdi@lists.oasis-open.org > Subject: Re: [xdi]
> > > > >Groups - XDI RDF v8 Comments-Barnhill (pdf) (XDI
> > > > >RDF v8 > Comments-Barnhill.pdf)
> > > > >uploaded > > > To be honest, I don't really
> > > > >understand the N-Segment syntax anyway. > > Why
> > > > >is > > s1 > p1 >
> > > > >o1 > p2 >
> > > > > o2 > > better
> > > > >than > > s1 > p1 >
> > > > >o1 > o1 > p2 >
> > > > >o2 > > ? > > Markus > On Tue, Mar 11, 2008 at
> > > > >4:29 PM, Giovanni Bartolomeo < >
> > > > >giovanni.bartolomeo@uniroma2.it> wrote: > Dear
> > > > >Bill, All, > > reading your comments about XDI
> > > > >RDF v8 ( >
> > > > >http://www.oasis-
> > > open.org/committees/download.php/27112/XDI%20RDF%20v8%20Comments-
> > > Barnhill.pdf
> > > > > > ) I've found this sentence: > > One problem
> > > > >with the 3-Segment syntax is that the N-Segment
> > > > >syntax uses > cross-references
> > > > >for > reification. This means 3-Segment syntax
> > > > >has to have a different notation > for a subject
> > > > >which is the > statement itself rather than the
> > > > >object of the statement. The 3-Segment >
> > > > >notation for this is a crossreference > within
> > > > >a cross-reference: (()). So a subject of (s/p/o)
> > > > >asserts s/p/o and > starts a new
> > > > >statement > whose subject is o, while a subject
> > > > >of ((s/p/o)) asserts s/p/o and starts a > new
> > > > >statement whose subject is > the statement
> > > > >s/p/o. For example to say that =Drummond is
> > > > >author of the > statement =Bill.Barnhill is
> > > > >a > contributor to the resource represented by
> > > > >@example we would use the
> > > > >XRI: >
> > > > >((@example/+dc+contributor/=Bill.Barnhill))/+dc+author/=Drummond.
> > > > > > > Well, I'm wondering how N3 syntax (and
> > > > >consequently X3 simple) addresses > this
> > > > >problem: > > If my understanding is correct,
> > > > >the N3 syntaxt > <s1> <p1> <o1> > <o1> <p2>
> > > > ><o2> > is equivalent to X3
> > > > >simple > s1 > p1 >
> > > > >o1 > p2 >
> > > > > o2 > what if I want to
> > > > >express that the whole statement <s1> <p1> <o1>
> > > > >is the > subject of <p2> <o2>? How this can be
> > > > >represented with X3 Simple? > Breaking into a
> > > > >new subcontext doesn't seem to help, as this
> > > > >explicitly > introduce a new
> > > > >subject! > s1 > p1 >
> > > > >/ > s2 >
> > > > > p2 >
> > > > > o2 > > Whereas I just
> > > > >want that the whole statement (s1/p1/o1) is the
> > > > >subject of > p2! > > What do you think? Am I
> > > > >missing
> > > > >something? > > Thanks, > Giovanni > > > At
> > > > >11.06 07/02/2008, barnhill_william@bah.com
> > > > >wrote: > > The document named XDI RDF v8
> > > > >Comments-Barnhill (pdf) (XDI RDF v8 >
> > > > >Comments-Barnhill.pdf) has been submitted by Mr.
> > > > >William Barnhill to the > OASIS XRI Data
> > > > >Interchange (XDI) TC document repository.
> > > > >Document > Description: View Document Details: >
> > > > >http://www.oasis-
> > > open.org/apps/org/workgroup/xdi/document.php?document_id=27112
> > > > > > Download Document: >
> > > > >http://www.oasis-
> > >
> open.org/apps/org/workgroup/xdi/download.php/27112/XDI%20RDF%20v8%20Commen
> > > ts-Barnhill.pdf
> > > > > > PLEASE NOTE: If the above links do not work
> > > > >for you, your email application > may be
> > > > >breaking the link into two pieces. You may be
> > > > >able to copy and paste > the entire link address
> > > > >into the address field of your web browser.
> > > > >-OASIS > Open Administration No virus found in
> > > > >this incoming message. > Checked by AVG Free
> > > > >Edition. > Version: 7.5.516 / Virus Database:
> > > > >269.19.19/1256 - Release Date: > 02/02/2008 13.50 > > > > > > > >
> > > >
> > > >
> > > >
> > > >
> > > > -------------------------------------------------------------------
> --
> > > > To unsubscribe from this mail list, you must leave the OASIS TC
> that
> > > > generates this mail. You may a link to this group and all your
> TCs in
> > > OASIS
> > > > at:
> > > > https://www.oasis-
> open.org/apps/org/workgroup/portal/my_workgroups.php
> > > >
> > > >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe from this mail list, you must leave the OASIS TC that
> > generates this mail. You may a link to this group and all your TCs in
> OASIS
> > at:
> > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php
> >
> >
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]