Re: ldp-ISSUE-75 (monotonicity): rdf:membershipProperty makes LDP PATCHing non-monotonic [Linked Data Platform core]

[ Hi John, it would help if in the snippets of conversation you keep the names
of those who were speaking. like I do below: ]

On 31 May 2013, at 23:03, John Arwe <> wrote:

> > This mean you may have to parse the whole graph to get to know how 
> > to deduce the ldp:includes relation I postit in ISSUE-79 
> [reads, rubs eyes, searches using browser, refreshes, searches again] 
> *what* ldp:includes relation ... in ISSUE-79 ? 

I meant ldp:contains sorry.

> [snipped a lot of remarks where the context had been snipped too much to make sense. Getting straight to the core point]
> > The ONLY place where you can have the default 
> > reasoning is in the LDPC itself! 
> Most reliable place (pesky trust issues!) probably.  Only place?  Hardly. 
No really.  You proved it yourself in your mail here:

You argued that 

{ ldpr a ldp:Container } 

does not imply by itself anything about the rdf:membership{Predicate,Subject} relations by 
itself. But the spec tells us that if you have the graph that came from <ldpr> that says 

{ <> a ldp:Container } 

and it does not say antthing about the  rdf:membership{Predicate,Subject} then you can deduce that

<> ldp:membershipPredicate rdf:member;
     ldp:membershipSubject <> .

That is an inferencing rule. It depends on the state of a particular graph, which is why it is closed world.
The inferencing rule is simple:

{ ?ldpc log:semantics [
                        log:includes { ?ldpc a ldp:Container } 
                        log:notIncludes { ?ldpc ldp:membershipPredicate rdf:member } ] }
 => { ?ldpc ldp:membershipPredicate rdf:member } 

But it is Ad-Hoc. So we would need to make this very clear in the spec. 
And presumably this ad-hocness should be cause for scrutiny.

> Best Regards, John
> Voice US 845-435-9470  BluePages 
> Tivoli OSLC Lead - Show me the Scenario 

Social Web Architect

Received on Friday, 31 May 2013 21:27:55 UTC