W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > July to September 2005

Re: subgraph/entailment

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Tue, 20 Sep 2005 17:30:16 -0400
Message-Id: <863b7550b82f29bbcfedd9bf65cdae25@isr.umd.edu>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Pat Hayes <phayes@ihmc.us>

Offline since it's not really helpful or relevant to the 
standardization effort, however entertaining.
On Sep 20, 2005, at 4:54 PM, Pat Hayes wrote:

>> On Sep 19, 2005, at 5:32 PM, Pat Hayes wrote:
>>
>>>> On Sep 19, 2005, at 2:55 PM, Enrico Franconi wrote:
>>>>
>>>>>> From: Pat Hayes <phayes@ihmc.us>
[snip]
>>> For myself, apart from the small group of logic police,
>>
>> I hope that you will be more judicious with your words while you are 
>> chairing.
>
> You guys are soooo sensitive.

Hmm. How does being condescending help mitigate the offense?

>  Would "logic mafia" (a more widely used term) be better?

No, nor would it be helpful. I object to my views being characterized 
and trivialized this way, especially by you, especially after about two 
weeks arguing your point while you weren't available. it took a *lot* 
of work on my part both on list and off to get him to *realize* (not 
understand once realized) the deductive closure view, and to "get" the 
told-bnode requirement. I don't see how I'm a member of a group of 
wankers concerned with purity (alone). I think I've acted quite 
pragmatically and sensible with a concern for application, deployment, 
and adoption.

So, this kind of talk on your part doesn't seem friendly, not in the 
least. I know Enrico didn't feel that way either. I don't see why I 
have to put up with it when it isn't necessary at all.

I don't mind it occasionally, but it seems like every standards talk we 
have ends up this way. I was *quite* hurt by clearly, from ALL the 
people I talked with, out of line abusive and personal comments you 
wrote to me on the social meaning list.

Furthermore, AS CHAIR you made a fairly rough comment toward Enrico. I 
don't see how this is fair, helpful, productive, or acceptable. I trust 
it is forgivable, but it would be nice to have some indication that you 
care about the effect of your words as well as the intent.

Even IF it were just my "oversensitivity", I think it would be 
reasonable to ask for *some* level of accommodation, consonant with my 
overall contribution, for example.

>>>  whose objections I can script in advance, *nobody* I have chatted 
>>> with has evinced the slightest interest in any formal semantic 
>>> issues at all. They tend to regard such matters as arcane academic 
>>> baloney.
>>
>> Pat, I have users and I have colleagues and I have collaborators. I 
>> represent an organization that pays fees to be a member in the W3C 
>> and supports semantic web work with an enormous amount of time and 
>> effort at many levels. We have priorities and mandates and desires. 
>> My job is to represent them in this group.
>
> OK, fair enough. Just out of interest, what organization is that?

Primarily the MindLab which has partnerships with Fujistu, NTT, 
Lockmart among others, and pending partnerships/current alliances with 
Cerebra and SAIC. I also consult for SAIC on their RDF/RDFS store and 
SPARQL engine (with Kendall). Also, as an academic research 
organization, I would like the specifications we produce to be useable 
for such things as our Semantic Web Services research (which, actually, 
does feed into Fujistu, NTT, and others). Oh, and Oracle. I've got them 
interested in using OWL for policy and I expect query to play a role 
there too. It certainly does in my product ideas.

>> When I talk to implementors like Boris Motik (Kaon2) whose system I 
>> am expected to evaluate for my users, and he, a very capable query 
>> person, is baffled and repelled by the specification, my job is 
>> harder. I don't *care* if that opens us up for sneering. Let whomever 
>> wants to sneer, sneer and jeer and leer away.
>>
>>> (See for example 
>>> http://www.shirky.com/writings/semantic_syllogism.html for a typical 
>>> attitude,
>>
>> Too bad that that article is a complete and total joke. I do not mean 
>> the attitude, I mean the content.
>
> But look, this is the audience we have to communicate with.

No, it isn't. Clay Shirky is not interested in being convinced and is 
actually quite inconsequential afaict. The audience I have to 
communicate are those in organizations who are considering investing a 
significant amount of time, energy, money, and credibility in semantic 
web technologies.

>  I'm not endorsing the content, only using it as an illustration of 
> the attitudes that we will find out there in the heads of the people 
> who will be implementing some of this stuff.

The day Clay implements ANYTHING, but more specifically, a SPARQL 
*anything* is the day I take him seriously. Maybe at all.

> (Ive had several 'right on!' emails in response to that posting, by 
> the way.)

I'm not saying there isn't a pro-rdf, somewhat anti-owl group. It's not 
the only one. I prefer to bridge, frankly.

I had positive comments on irc in public from Jeen and Steve Harris who 
were concerned with RDFS being clearly in the mix.

I don't claim to represent *every* view, merely a significant one. You 
didn't even know what that group *IS* and yet you feel happy to dismiss 
them brusquely. To that I say: Bah! :)

> If you use terms like 'entailment' and them tell them that there are 
> six (so far, and counting) distinct kinds of entailment defined, that 
> they have to get right and/or choose between, how many converts will 
> you get to the great SWeb cause? We are in danger of creating a 
> logician's mini-paradise here that will simply get ignored by the rest 
> of the planet.

If they can handle XML Schema, which they can, they can handle this. 
Most of it will only be of concern if you need it to be.

>>> or http://www.disobey.com/detergent/2002/sw123/ for a more 
>>> enthusiastic one. Both among the first 20 hits on 'semantic web' .)
>>
>> Er...yes? This is "I like RDF and dislike RDF/XML and had trouble 
>> getting into RDF because of RDF/XML". That's fine. I don't see it as 
>> anti-more expressiveness. Oh I see. He doesn't mention inference et 
>> al. So?
>
> So, do you want (folk like) him to be able to read the spec and 
> implement a simple SPARQL processor?

Well, let me burn this straw (i'm amazed that you cast this after the 
telecon): I don't see that the spec can't be clear here to both 
audiences. Right now, I frankly don't believe it's truly clear to ANY.

Also, part of the job of a spec is to be *right* with full coverage. 
The subsequent job of the community and specwriter's is to explicate 
things for user and implementors. I'd MUCH rather get a question on a 
mailing list about "what does this entailment stuff mean for my 
implementation" then let people have the illusion of understanding. 
I've done this for Fujistu, and SAIC, among others. It actually works 
out well.

I'd also like a variety of high quality implementations,and that's the 
audience I care about.

> Which do you think is going to make most sense to him: to read about 
> substitutions for variables and subsets of triples, or to read about 
> entailment, with references to two documents describing six model 
> theories, three of which are described in a style so dense and 
> opaquely written that at least two professional academic logicians I 
> know have given it up as unreadable?

Which three? The only one I have trouble with is OWL Full, and I don't 
spend a lot of time there.

Plus, I have no trouble putting informative exposition in document 
saying, "Many will only care about simple through RDFS entailment, and 
here's an alternative way to understand them".

[snip]
> What does it mean to apply to a more expressive language? It will 
> apply as it stands to any - read my lips, *any* - RDF graph.

To query OWL DL data it's tricky because to have to generate the graph 
from the syntax of the formula of the deductive closure. I've not 
worked out the details, but it is cumbersome to specify things that way 
to say the least.

> If your language is encoded in RDF, and you know how the encoding 
> works, then you can use that knowledge plus SPARQL to get you 
> somewhere; but SPARQL isn't going to do that work for you, or 
> magically extend itself to be a general-purpose logical inference 
> protocol. What else did you expect, for goodness' sake?

I expect it to be able to do conjunctive (and result disjunctive) query 
of the data of an owl ontology. Which it can easily do with a bit of 
tweaking. We've had an implementation of RDQL in our reasoner Pellet 
for about a year and half (motivated by OWL-S...wanting to specify and 
evaluate preconditions against OWL ontologies as state-of-the-world). 
We even have one that mixes syntax queries with data queries (though 
there are tricky issues that we got wrong for a while). The Fujistu 
guys loved this and are trying to incorporate it into a product.

So, I expect at least that (the data). Mindswap made it clear from the 
start that we were interested in this sort of thing. And got positive 
response. We were willing to defer on the details so long as the 
general forward compatibility was there.

I don't think there is a technical problem with this. I don't see why 
you do. There are technical choices to make, and I have preferences on 
how they are made.

Cheers,
Bijan.
Received on Tuesday, 20 September 2005 21:31:03 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:24 GMT