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Re: Important Question re. WebID Verifiers & Linked Data

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Thu, 22 Dec 2011 07:41:26 -0500
Message-ID: <4EF32576.5040101@openlinksw.com>
To: public-xg-webid@w3.org
On 12/22/11 3:48 AM, Henry Story wrote:
> On 22 Dec 2011, at 04:42, Kingsley Idehen wrote:
>> On 12/21/11 3:45 PM, Patrick Logan wrote:
>>> See below...
>>> On Wed, Dec 21, 2011 at 8:27 AM, Henry Story 
>>> <henry.story@bblfish.net <mailto:henry.story@bblfish.net>> wrote:
>>>     On 21 Dec 2011, at 14:58, Kingsley Idehen wrote:
>>>     >
>>>     > Please understand that RDF != Linked Data. It's just one of
>>>     the options for creating and publishing Linked Data.
>>>     I think it would be very nice to have a formal spec on what
>>>     Linked Data is. We do have a few for
>>>     RDF.
>>> Yes, please. I understand the RDF-related specifications. And I 
>>> understand the general notion of "linked data". I am someone 
>>> following the WebID effort, and who is contemplating the costs and 
>>> benefits of supporting it in my products at some point.
>>> Unless I see a WebID specification (or a more general "world-wide 
>>> linked data specification") for how to support linked data beyond 
>>> RDF, how can I estimate the costs and benefits of supporting linked 
>>> data beyond RDF?
>>> Please understand that "publishing and consuming any and all 
>>> possible interpretations of 'linked data'" is probably impossible.
>>> So what are the specific requirements?
>>> -Patrick
>> Patrick,
>> Here are the fundamental requirements:
>> 1. a Data Item (Object or Entity) is uniquely identified by a URI 
>> based Name
>> 2. use de-referencable URIs as Names that resolve to *descriptor* 
>> documents (resources) that describe the URI's referent
>> 3. descriptor documents (resources) should *consist* or *bear* 
>> structured data in the form of eav/spo triples (or 3-tuples) 
>> statements that collectively form a directed graph pictorial that 
>> coalesces around the description subject's URI .
>> You can make statements eav/spo statements using a variety of syntaxes.
>> You can serialize eav/spo bearing resources across the wire using a 
>> variety of data serialization formats.
>> You can leverage HTTP as a low cost and effective mechanism for:
>> 1. de-referencable URI based Names
>> 2. negotiation of data serialization formats between servers and 
>> clients (user agents).
>> The WebID spec can require or suggest a number of common formats for 
>> eav/spo triple transmission as the basis for effective bootstrap.
>> The WebID spec should never (overtly or covertly) be a tool for 
>> fighting or prolonging  syntax of format wars re. eav/spo triples.
>> The WebID spec should never leak the abstraction inherent in URIs by 
>> mandating http: scheme URIs.
>> The WebID spec should never compromise the fidelity of Linked Data by 
>> favoring a particular style of de-referencable URI.
>> The WebID spec is a spec. It shouldn't attempt to teaching software 
>> engineering.
>> All of the above is possible without adversely affecting WebID. In 
>> short, all of this will make WebID attractive to much broader 
>> developer profiles that extend beyond the RDF based Semantic Web 
>> community.
>> What's the difference between RDF and EAV?
>> RDF explicitly (via spec) requires the use of URIs in S, P, and O 
>> (optionally) slots of triple statements. It also handles typed 
>> literals and language tags. Basically, it caters for locale issues 
>> and i18n.
> In fact RDF semantics does not do this. It is just the RDF 
> serialisations that do, and for not such bad reasons. RDF semantics 
> allows numbers in predicate positions, though these don't have much 
> use there. There is even an example in the spec about this here 
> http://www.w3.org/TR/rdf-mt/ !

Put differently, RDF introduces (as part of its spec) URIs to EAV. 
That's the fundamental point.
> You can map every EAV to SPO, and can in fact infer from each. SPO is 
> much cleaner theoretically than EAV as it is purely relational, and 
> everything can be mapped down to relations in the end.

S-P-O and E-A-V are 3-tuples with different letters. The use of URIs is 
where RDF starts to be more specific. The aforementioned specificity 
extends to typed literals, language tags, and i18n.

> So really all that Kinglsey is doing is change the language because he 
> thinks that it is the language that was the problem with RDF, where in
> fact I think there were quite a number of other issues that were the 
> problem, such as no decent tooling and no understanding from the 
> developers
> of even REST at the time. XML had just came out and it promised to do 
> everything, which shows just how syntactically people were thinking at 
> the time.

No, since I know myself pretty well, here is what I am doing:

I am trying to make the issue of Linked Data (foundation layer of the 
Semantic Web Project) more accommodating. Achieving this accommodation 
means introducing missing genealogy to the RDF narrative.

> In the mean time Java came out and .net and the idea that multiple 
> languages could be used to program to the same machine. That the 
> machine itself could be virtual. And so the notion of semantics is 
> very widely spread in the procedural space.


Semantics has been in computer science since forever. RDF isn't the 

>  So in my view this is the wrong time to shift.

The fact that you think I am seeking a shift is symptomatic of the 
fundamental issue we are having re. communications. Put differently, 
your arguments right now are exactly the same as the arguments you were 
attempting to make about slash vs hash URIs yesterday. Eventually, you 
found out that it was down to a bug.  Please re-read yesterday's thread. 
Until you found the bug you were making a contradictory argument. You 
are repeating it again (albeit different context) right now.

> It is as if you had asked people about Object Oriented programming in 
> 1992. There would have been huge arguments about its complexity (c++) 
> or academicity (eifel, ...), then Java come out and 5 years later you 
> could not program without doing OO.

The problem with OO languages is that Object Theory isn't a programming 
language specific thing. Linked Data is about unshackling Object Theory 
from programming languages.

Data Objects can exist independent of any programming language, 
operating system, or dbms engine specificity. When all is said and done, 
this is what AWWW is delivering to the world, the final unshackling of 
Data from Code.

> OWL is just OO for relations btw.

OWL is about Semantic Fidelity for relations. These relations take the 
form of eav/spo 3-tuples (triples).

>> EAV isn't as specific as RDF with regards to the items above. At the 
>> same time EAV is well known, and doesn't carry the political baggage 
>> of RDF.
> I am not sure there is a Political baggage of RDF.

We view the world through completely different "context lenses". I know 
the letters R-D-F carry huge political baggage that continues to impede 
comprehension and adoption of the Semantic Web vision.

I can separate concepts for syntaxes (programming language or markup) . 
You claim you can, but you are always talking about parsers. I don't 
think about parsers when working on WebID, Linked Data etc.. I think 
about: data objects, locations/addresses, negotiable representation, 
relations, and the semantic fidelity of relations.

> All linked data does RDF and it is growing very fast. People are 
> understanding that RDF is about semantics and relations. and I get 
> very little negative feedback about RDF. Even Facebook is publishing 
> Turtle now!

Again, here is where you are incorrect. Facebook is publishing Linked 
Data and that has zilch to do with Turtle, which is just another syntax 
for expressing eav/spo based triples as well as being yet another 
across-the-wire serialization format. When Facebook officially decided 
to go with Linked Data I wrote a note [1] deconstructing what they did, 
I encourage you to read it.

>> What's the difference between RDF and Linked Data?
>> There is nothing in the RDF spec (even as I write) that specifies the 
>> behavior of URIs used in SPO triples. For instance RDF doesn't 
>> explicitly distinguish between a URI that serves as a Name and a URI 
>> that serves as a Resource Locator (Address).
> And that is very good. RDF is about semantics and logics. Linked Data 
> is pattern of publication of this data. Linked Data still has to be 
> fully specified by the W3C, but it is obviously exactly how Tim 
> Berners Lee intended RDF to be used.

TimBL did not intend for any specific syntax. He had a clear vision for 
InterWeb scale Linked Data. RDF happened to be a vehicle for vision 

You are still failing to accept that RDF isn't the progenitor.

> This was not understood by the RDF logicians he employed necessarily 
> because they had a different background.
>> Linked Data is very specific about URI behavior. It expects URI based 
>> Names and Addresses to be distinct.  This is why it's always 
>> problematic to infer (overtly or covertly) that RDF == Linked Data. 
>> The *truth* of the matter is that RDF is one approach to constructing 
>> directed graph based descriptor resources (comprised of eav/spo 
>> triples) that result in Linked Data at various scales (local area 
>> network or wide area network e.g., the InterWeb).
> RDF is mathematically defined, therefore it covers all ways of doing 
> relational stuff. you can of course re-invent it, but then it would 
> take no time to map that back to rdf, so your time would be wasted.

Again, you are making a comment short on deeper information. If you want 
to understand what's going on with relations and data I suggest you 
digest an article I stumbled across recently titled: A co-Relational 
Model of Data for Large Shared Data Banks [2].
> I will therefore continue speaking in terms of RDF and Linked Data.

You can speak in terms of RDF and Linked Data. Just don't try to infer 
that RDF is the only option for producing Linked Data since that's an 
utter fallacy. Also, don't claim WebID is about Linked Data if it 
doesn't support Linked Data principles. Again, remember, you found a bug 
yesterday in your code. Prior to finding a bug in your verifier, you 
were heading down a very slippery slope re. your arguments about why 
Linked Data clients should be discriminating against a particular style 
of de-referencable URI.

> Those are clearly understood, extremely well specced out, and there is 
> now 12 years of accumulated knowledge in that space. We  also have the 
> tools to do things there.

I am no stranger to RDF tools.
>  Plus we are at the W3C here and we can use the vocabulary. NASA uses 
> RDF, governments use RDF, companies are using them, social networks 
> are using it. All in more and more linked data manners.

Any you feel you need to educate me about who is using RDF to do real 
work across industry?

> Perhaps some crowds need to be talked to in terms of EAV, but we are 
> not going to write a spec in latin to make the vatican happy too either.

I haven't asked you to put EAV into the WebID spec. I've asked you to 
make up your mind about WebID re., the following:

1. Linked Data
2. Architecture of the World Wide Web.

Yesterday, you were basically "walking the plank" on both fronts. Now 
you've fixed the bugs in your service, and we just might be back on 
track re. the suggestions you make. Please remember, this thread is 
about WebID Verifiers and Linked Data (which is an application of AWWW). 
Yesterday, you made contradictory suggestions re:

1. URIs  -- slash or hash based HTTP scheme URIs
2. HTTP -- re. 303 redirection.


1. https://plus.google.com/112399767740508618350/posts/6cqa1Sxk5KV-- 
What Facebook Can Teach Us about Bootstrapping Linked Data at InterWeb 
2. http://queue.acm.org/detail.cfm?id=1961297 -- A co-Relational Model 
of Data for Large Shared Data Banks .

> Henry
>> Regards,
>> Kingsley Idehen	
>> Founder&  CEO
>> OpenLink Software
>> Company Web:http://www.openlinksw.com
>> Personal Weblog:http://www.openlinksw.com/blog/~kidehen
>> Twitter/Identi.ca handle: @kidehen
>> Google+ Profile:https://plus.google.com/112399767740508618350/about
>> LinkedIn Profile:http://www.linkedin.com/in/kidehen
> Social Web Architect
> http://bblfish.net/



Kingsley Idehen	
Founder&  CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
Google+ Profile: https://plus.google.com/112399767740508618350/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen

Received on Thursday, 22 December 2011 12:41:50 UTC

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