W3C WebOnt Working Group IRC logs for 2002-01-14

These are the automatically generated logs from the W3C WebOnt Working Group IRC chat

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[09:33:03] logger

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Users on #webont: @logger

[14:11:13] DanC

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[14:11:32]

* em wonders if there is a webont channel for f2f?

[14:11:34] DanC

[Lucent host]: Sheila M and I are running a workshop...

[14:11:52]

* DanC is coming from the ftf; dunno whether this channel will be "official" in any way

[14:12:04]

* em waves to DanC

[14:12:59] DanC

agenda: http://www.w3.org/2001/sw/WebOnt/ftf1.html#agenda

[14:13:05] DanC

dinner tonight is at 6pm

[14:14:25] DanC

previously mentioned workshop: e-Services and the Semantic Web http://www-db.research.bell-labs.com/essw2002/

[14:17:32] DanC

==== JimH convenes

[14:17:41] DanC

JimH models WOWG t-shirts

[14:18:21] DanC

=== Roll Call

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[14:19:25] DanC

Finin accepts scribe duties for the first session.

[14:19:35] DanC

-- Finin, UMD

[14:19:50] sandro

PFPS was making noises about making some of the session a telecon and inviting some of us not in the WG....?

[14:19:52] DanC

-- Connolly, W3C

[14:20:02] DanC

-- PeterPS, Bell Labs/Lucent

[14:20:06] DanC

-- IanH, U Mann

[14:20:15] DanC

-- Shimizu (sp?), INTAP

[14:20:29] DanC

-- Carroll, HP

[14:20:32] DanC

-- Smith, EDS

[14:20:39] DanC

-- Fensel

[14:20:41] DanC

-- Decker

[14:20:47] DanC

-- Volz

[14:20:53] DanC

-- McGuinnes

[14:20:58] DanC

-- Hefflin

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-- Hellman, Unicorn

[14:21:09] DanC

-- Obrst, Mitre

[14:21:14] DanC

-- Van Harmelen (sp?)

[14:21:15] DanC

-- Dean

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-- Gibbins

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-- Dale, Fujitsu

[14:21:30] DanC

-- Jos De Roo

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-- Olivry, EDF

[14:21:44] DanC

-- Sabou (sp?), Mitre

[14:21:50] DanC

[...]

[14:21:51] DanC

-- Miller

[14:21:54] DanC

-- Brickley

[14:21:57] DanC

-- Schriber

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[..] = Barnette

[14:22:24] DanC

JimH: one or two are still expected.

[14:22:40] DanC

here = irc.openprojects.net

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[14:23:03] DanC

PeterPS: NOTE WELL: I'm not sure the logistics for getting in the room will be exactly the same tomorrow.

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[14:25:08] DanC

JimH: I've been asked "what are we expected to produce"?

[14:25:18] DanC

JimH: [cf charter, Director's Decision]

[14:25:54] DanC

DanC has changed the topic to: WebOnt ftf, NJ http://www.w3.org/2001/sw/WebOnt/ftf1.html

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[14:26:24] DanC

JimH: we were not chartered to build, from scratch, a new language; we're chartered to build on existing stuff.

[14:26:48]

* DanC notes that the chair did designate this channel for minutes

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JimH: we're not doing content ontologies; contrast with SUO

[14:28:53] DanC

JimH: we're trying to find the suite spot between expressiveness and utility.

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* DanC welcomes tim, our scribe for this session

[14:30:27] DanC

JimH: [1.2.2 Formal Semantics ...]

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[14:31:27] tim

jimh: need to document how owl differs from other languages

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jimh: this documentation needs to describe and be accessible to different user communities

[14:32:21] tim

question: who is the target reader of our standards documents?

[14:32:41] tim

jimh: developers plus users

[14:33:03] tim

jimh: look at the daml documents as examples

[14:34:12] tim

jimh: danc gets up

[14:34:38] tim

danc: we're here to get a technology deployed

[14:34:51] tim

danc: whatever is required to do this is what we should do

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danc: experience in the xml schema group was that they needed two spec documents

[14:36:13] tim

danc: we'll go until 10am

[14:36:57] tim

danc: looking at http://www.w3c.org/2001/sw/WebOnt/

[14:37:27] tim

danc: look at background references

[14:38:21] tim

danc: look at http://www.w3.org/Guide/

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danc: looking at http://www.w3.org/Consortium/Process-20010719/

[14:39:22] tim

danc: is describing W3C

[14:40:53] tim

jimh: we might need to redo the IP form for member orgs

[14:41:39] tim

danc: we're are chartered to produce a technology that can be implemented on a royalty free basis

[14:42:15] tim

danc: the format of w3c tech reports is fixed. we have to live with it. checked by machine.

[14:44:48] tim

danc: describing the "last call" part of the process

[14:45:25] tim

danc: any other working group or even a member of the public can raise issues to say whether or not a working group is "done".

[14:45:58] tim

danc: looking at http://www.w3.org/Consortium/Process-20010719/tr.html#last-call

[14:47:27] tim

pps: describing the networking environment for the meeting

[14:48:51] tim

danc: when we publish working drafts and in what form are up to us

[14:49:18] tim

danc: we are required to publish a working draft every three months

[14:49:53] tim

jimh: use case docs will come out as a working draft

[14:50:11] tim

danc: working drafts elicit feedback

[14:52:59] tim

danc: simplicity is a big survival characteristic for these kinds of standards

[14:53:23] tim

danc: a wg needs to stick around for ~6 months after the recommendation

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[14:55:54] tim

danc: back to reviewing parts of http://www.w3.org/2001/sw/WebOnt/

[14:56:53] tim

jimh: xml-schema is not on this list, is this intentional?

[14:57:48] tim

comment: we need to be able to say how what we are doing is different from xml schema

[14:58:02] tim

danc sits down

[14:58:17] tim

pps: one more item before break -- the name.

[14:58:33] tim

jimh: we had a resolution on last telecon

[14:58:38] tim

pps: owl is fine

[14:58:55] tim

jimh: we resolved in the last telecon that we will call the language OWL.

[14:59:24] tim

danc: oit's as official as it will get before submitting the recommendation

[14:59:56] tim

jimh: doesn't change the name of the working group, webont

[15:00:51] DanC

s/submitting the recommendation/publishing a working draft/

[15:03:25] tim

___

[15:03:25] tim

<*,*>

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[`-']

[15:03:25] tim

-"-"-

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danc: reviws schedule for rest of day

[15:04:33] tim

jimh: reviewing tomorrow's schedule

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* DanC wonders if anybody's tring to call in

[15:05:21] tim

a call just came in on the conference call

[15:05:34] tim

we answerewd but no one was there.

[15:05:42] tim

perhaps it was a telemarkerer

[15:05:54] tim

jimh: we are now on break until 10:30

[15:06:21] tim

and so it goes

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======= next session

[15:38:29] DanC

Frank vH accepts scribe duties for the session

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[15:41:22] DanC

did Ian accept an action to archive his presentation materials, JimH?

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* DanC suggests everybody say a prayer to the demo-gods...

[15:42:27] tim

?

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* las is happy to say it works!

[15:43:53] DanC

logger, pointer?

[15:43:53] DanC

See http://ilrt.org/discovery/chatlogs/webont/2002-01-14#T15-43-53

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[15:45:14] DanC

slide 4.

[15:45:35] DanC

Q: 1st bullet: there's lots of XML Schemas and b-to-b stuff going on...

[15:45:56] DanC

so when was that claim made?

[15:46:41] DanC

A:most stuff is still only human-readable.

[15:46:56] DanC

A:XML Schema approach seems to require pre-existing knowledge of what documents mean.

[15:48:26] DanC

hmm... does DAML+OIL have ABox/TBox?

[15:48:45] DanC

hmm... does it really have expressions? it's all just built with 2-place predicates, no?

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[16:04:25] JosD

do we want to say: for this document we have the UNA ???

[16:05:11] DanC

JimH, are you keeping an eye here?

[16:05:25] DanC

I wonder if we could have a session with the RDF validator, which makes pictures from RDF syntax

[16:05:47] DanC

MikeDean, could I borrrow/steal some of your time tomorrow for playing with the RDF validator?

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[16:07:13] em

DanC, do you have IsaViz loaded on your laptop? This may make more sense as you can interact with the images produced

[16:07:21] DanC

isaViz: nope

[16:09:01] DeborahMcGuinness-SWWS

slow response to josD - yes

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[16:17:15] DeborahMcGuinness-SWWS

also users may want to apply the closed world assumption at some point on a knowledge base (similar to people wanting to make the unique names assumption for some knowledge base)

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[16:18:49] DanC

re syntactic sugar: how about noting a minimal basis... for implementors, the terms that are sugar are much easier to implement.

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* DanC asks Frank to be sure he gets this Q/A stuff

[16:21:21] DanC

Q: what's up with this xxxQ stuff? when do we use it?

[16:22:20]

* DanC realizes Frank isn't using this channel for his notes.

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[16:28:19] DanC

Lynn: hasClassQ is a mechanism for making an n-ary predicate in RDF, yes?

[16:28:22] DanC

PeterPS: yes

[16:29:27] DanC

JimH, I think your point did get lost in the technical discussion; I think your point was: if we do something wierd (i.e. making a 5-ary relation in a syntax that's designed for 2-ary relations) we'll have to explain it specially.

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[16:29:51] las

Specifically, hasClassQ AND minCardinalityQ (or max, etc.) together define a 5-tuple: subject, property=hasClass(Q), objectOfHasClass, property2=cardinality(Q), objectOfCardinality

[16:30:45] las

I agree that JimH's point was lost and apologize for distracting, but thought it was important (a) to make sure I understood and (b) if possible, to increase the number of other people in the room who thought they understood, to (or even thought correctly they understood :o) )

[16:37:41] DanC

yes, there is another important point there: RDF is heavily-biased to 2-ary relations. Doing n-ary relations hurts.

[16:38:37]

* sandro would argue that it only hurts once, and you quickly get used to the pain with a little syntactic sugar.

[16:39:00] sandro

As with LISP, which also only does binary relations, at the lowest level.

[16:39:15] DanC

hmm... I think the pain is pretty long-lived. It seems economical to push the pain down into the RDF layer.

[16:40:00]

* sandro also wouldn't mind chucking 3-tuples for an n-tuple model, if that's really an option,.

[16:40:30] sandro

but there may be drawbacks I haven't figured out, either. It's a big decision.

[16:40:33] DanC

yup

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[16:48:10] DanC

hmm... is this Oiled thing OpenSource?

[16:48:31]

* DanC surfs around... http://img.cs.man.ac.uk/oil/

[16:49:35] DanC

hmm... http://img.cs.man.ac.uk/oil/license.html looks OpenSource-happy to me

[16:50:21] DanC

oops, no, it's not: "Permission is not granted to disassemble, decompose,

[16:50:22] DanC

reverse engineer, or alter this file or any other files in the

[16:50:22] DanC

package. "

[16:52:54] DanC

re decidability: I wonder if I should bring up that this isn't a requirement here.

[16:53:08] DeborahMcGuinness-SWWS

sometime that is worth discussing

[16:53:21] DeborahMcGuinness-SWWS

but the discussion will not be short

[16:53:33] DanC

s/isn't a requirement/isn't yet a requirement/

[16:58:41] DanC

hmm... having a top class seems like it would bring up Russel's paradox.

[16:58:54] DanC

i.e. the class of all classes that are not members of themselves.

[17:00:15] JosD

i.e. see http://www.agfa.com/w3c/euler/russell.axiom.n3 no?

[17:01:00] DanC

this abox/tbox stuff isn't in my background. Is it familiar to anybody else?

[17:01:40] las

Dan, it is standard (i.e., obscure) KR, but you are absolutely right that Ian should not be taking it for granted.

[17:03:20] las

Google reveals http://www.hpl.hp.com/semweb/download/DescriptionLogicsIntro.pdf (see esp. p. 10) when queried on abox tbox. Seems appropriate enough....

[17:04:13] las

(abox = assertions, i.e., ground facts; tbox = terminology, e.g., class relations

[17:04:14] las

)

[17:05:40] Jah-wowg

the hard part is remember which is which if you're not a DL person - I always forget if it is A for Axiom or T for Theorem or...

[17:11:29] DeborahMcGuinness-SWWS

we should add a pointer to this

[17:11:49] DeborahMcGuinness-SWWS

actually the distinction started to disappear in DLs after constructors like oneof and filler ended up on concept languages

[17:11:55] DeborahMcGuinness-SWWS

t box used to just be the schema

[17:12:03] DeborahMcGuinness-SWWS

and abox used to just be the instances

[17:12:18] DeborahMcGuinness-SWWS

once you could put things like clinton in the tbox with constructors like one-of

[17:12:29] DeborahMcGuinness-SWWS

most people in the dl community started dropping the distinction

[18:00:18] DanC

====== lunch ends

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* nmg scribes

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[18:02:54] nmg

====== Use Case Discussion

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====== Collection Management (Schreiber)

[18:03:28] TimFinin

?

[18:04:32] nmg

danc: use case document motivates requirements

[18:05:50] nmg

jimh: requirements doc in three parts: 1 compelling use cases (5ish)

[18:05:57] nmg

2 requirements arising from use cases

[18:06:22] nmg

3 appendix containing additional use cases not contributing to 2

[18:06:55] nmg

jimh: requirements section is a 'living document'

[18:08:51] nmg

jimh: requirements arising from existing use cases not completely consistent

[18:09:49] nmg

jimh: purpose of this meeting is to reduce these to a consistent set

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[18:11:25] DanC

DanC: what we're looking for in use cases is: can we use this as a finish line? i.e. does pretty much everybody in the group agree that "if we can't do that, we're not done."?

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[18:11:45] DanC

JimH, has gus accepted an action to archive his presentation materials?

[18:15:10] nmg

guus: requirement arising from a common modelling issue: classes as instances of classes

[18:15:59] DanC

Velente et al... anybody else read it? pointer?

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[18:16:57] DanC

[repeat, since maybe Deb can help]

[18:16:58] DanC

Velente et al... anybody else read it? pointer?

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[18:17:44] nmg

ianh: how useful is this metaclass approach?

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[18:18:43] DanC

re Valente, googling around produced http://citeseer.nj.nec.com/253542.html ; am I close?

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[18:19:00] nmg

guus: this arises in both stephen buswell's aero example and jjc's arkive example.

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[18:19:33] nmg

las: many systems, including frame and oo systems in which metaclasses are used in this way

[18:19:53] nmg

ianh: semantic are confused

[18:20:31] DeborahMcGuinness-SWWS

this could be the valente ref: (no hot link sorry - found on google - "Building and (Re)Using an Ontology of Air Campaign Planning&quot;. A. Valente, T. Russ, R. MacGregor, and W. Swartout. IEEE Intelligent Systems 14(1), 1999.

[18:20:43] nmg

las: existing literature and user community make use of this - may be 'wrong', but should be noted

[18:20:50] nmg

action: las to explain further

[18:21:31] DanC

if you would, please put ACTION in all caps. easier to search for

[18:21:46] nmg

guus: daml+oil and rdf allow it, but semantics are problematic

[18:22:03] nmg

guus: req #2: constraints

[18:22:08] DanC

nmg, there's no need to re-capitulate the presentation materials here.

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[18:22:14] nmg

okay, noted

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[18:27:10] nmg

danc: point of order - f2f useful for conducting polls

[18:27:58] nmg

danc: on both use cases and requirements

[18:28:24] nmg

danc: subgroup membership does not exclusively represent members' interests

[18:29:27] nmg

jimh: not for now - breakout sessions tomorrow

[18:31:29] nmg

jimh: as each requirement is presented, take straw poll of members, record roughly (strongly agree, etc)

[18:32:45] nmg

POLL: classes as instances of other classes (strong agree)

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[18:35:16] nmg

POLL: definitional constraints (mostly unclear)

[18:35:23] DanC

no in favor.

[18:35:56] DanC

in particular: the x.length < y.length isn't (clearly) doable in DAML+OIL

[18:39:47] DanC

default: several in favor, several against...

[18:40:04] TimFinin

what was the default for the group?

[18:40:56] DanC

repoll

[18:41:06] DanC

default requirement yes: several

[18:41:14] DanC

not a req: many

[18:41:39] nmg

POLL: default knowledge (mostly in favour, some against)

[18:41:59] nmg

CORRECTION: default knowledge (mostly against, some in favour)

[18:44:01] nmg

las: individual decisions rely on other issues - votes often qualified

[18:45:36] DanC

hmm... a lot of his requirements look like rules to me.

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[18:47:33] DanC

"his" meaning the ones he's presenting

[18:48:31] JosD

DanC, how so for part/whole

[18:50:19] DanC

well... parts of airplanes inherit from the whole, but parts of dressers don't. i.e. you need rules to say which is which. or: you can express the difference with rules.

[18:50:27] nmg

POLL: part/whole relations (mostly opposed, few in favour)

[18:52:35] JosD

DanC, yes that expressing of the difference is indeed an interesting idea!

[18:53:42] nmg

POLL: property typing (mostly in favour, couple against, few don't care)

[18:54:41] nmg

jimh: general action on all those presenting to provide electronic copy of presentation materials for archival

[18:54:49] nmg

ACTION: guus to provide slides

[18:56:00] nmg

====== Content Interoperability (Leo Obrst)

[18:56:18] nmg

presentation materials are those mailed to www-webont-wg

[18:56:59] nmg

http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/0066.html

[18:57:28] DanC

more abstract: bummer. I like use cases to be concrete

[18:59:37] nmg

leo: requirements generalised from 22 use cases

[19:02:51] nmg

jimh: should not vote on each requirement - too many. leo should select key ones.

[19:03:27] nmg

POLL: inter-ontology references 3.1.1 (mostly in favour)

[19:05:37] nmg

POLL: ontology mapping rules, features 3.1.3 (jimh rules poll out of charter)

[19:06:44] DanC

hmm... that was the first time the chair curtailed discussion based on the charter. perhaps that bears explanation

[19:06:46] nmg

POLL: ontology composition language 3.1.4 (mostly in favour)

[19:10:52] nmg

POLL: inter-ontology sysnonyms/aliases 3.1.8 (mostly in favour, no against, few don't care/know)

[19:13:22] nmg

POLL: ontology approximation 3.1.11 (mostly against, few don't care, couple in favour)

[19:17:26] nmg

POLL: inter-ontology validation 3.1.12 (annotation/tagging wrt consistency) (most in favour, some disagree, significant number of don't know/care)

[19:19:13] DanC

chair notes that we'll get back to ontology version management later in the "general requirements" section

[19:19:51] DanC

metaknowledge: this one is hard for me; I want it, but probably not in the OWL later

[19:19:53] DanC

layer

[19:21:13] nmg

(not under scribe hat) ditto here for reification in general

[19:23:11] JosD

say res1 prop res2 in which res1 and res2 happen to be set of statements (by value!)

[19:25:49] JosD

(by value is either deref res uri or identify by content e.g. N3's { } )

[19:26:27] nmg

jjc: (commenting on 3.4.7) i18n very important

[19:26:58] nmg

====== Services (Stefan Decker)

[19:27:13] nmg

reqs mailed to www-webont-wg

[19:27:18] nmg

http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/0083.html

[19:27:48] DanC

nmg, pls do record this discussion

[19:28:25] DanC

Decker: before I start, I'd like to note that a lot is going on in Web Services in a way that's disconnected from Ontologies.

[19:28:48] DanC

... I suggest we think about how to change that. I don't have much of an idea of how.

[19:28:54] DanC

... what gets money is XML technology.

[19:29:54] Jah-wowg

...what gets money is were XML technology focuses?

[19:31:55] nmg

re: efficient inferencing, assumption is made that inferencing will be performed on small devices (rather than on external services called by the devices)

[19:33:06] nmg

fvh: three reqs here: simple and concise lang, layering, defn of limits

[19:34:01] nmg

POLL: language must have a small footprint (mostly against)

[19:34:48] nmg

POLL: language defn is organised in layers (mostly in favour, some against, few neutral)

[19:35:03] nmg

danc: layering not a requirement for this wg

[19:35:41] nmg

POLL: precisely described semantics (jimh overrules vote since this is in the charter)

[19:36:13] DanC

to clarify: from this WG, I don't need more than one layer. I do need layering between this group's language and other groups' langauges.

[19:38:05] nmg

(re: complex types) danc: example given is dates - these are already defined in XML Schema

[19:39:06] nmg

jimh: definition of inequalities (date ranges, eg - see guus' example)

[19:40:08] nmg

danc: XML Schema is a w3c spec, and terms from that spec should be used by this wg in the same way that they are used in XML Schema (complex types)

[19:40:18] nmg

danc: dates (in XML Schema terms) are not complex types

[19:41:09] nmg

POLL: datatypes in language (mostly in favour)

[19:41:42]

* TimFinin slaps TimFinin around a bit with a large trout

[19:42:07] nmg

danc: requirements should be derived from use cases - this (travel planning) is a good use case

[19:43:30] nmg

jimh: this use case requires range types

[19:45:43] nmg

POLL: ability to express relations between types (eg. inequalities on numbers) (jimh postpones)

[19:46:00] nmg

ACTION on Stefna's group to discuss further tomorrow

[19:49:06] nmg

stefan: (re: unique reference for ontology, class member ship in ontology) need to be able to tell where a class comes from

[19:49:58] nmg

danc: rdfs:isDefinedBy

[19:51:56] nmg

danc: also, ontology defn includes a statement to the effect that it is an ontology defn

[19:53:31] DanC

being able to name ontologies and relate classes to them

[19:53:44] nmg

POLL: ability to give ontologies names and the ability to denote membership of a class in an ontology (mostly in favour, few opposed, few don't know)

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[19:55:48] nmg

danc: (re: ontology versioning) ontology as artifact with state

[19:56:03] nmg

jeffh: postpone this discussion to general requirements

[19:57:00] nmg

(re: service/oracle for providing instance data)

[19:57:14] nmg

fvh: also known as procedural attachment

[19:57:27] nmg

danc: existing patent in this area

[19:57:32] DanC

PeterPS: at this point, there's an intellectual property issue. McGuinness and I are authors of a patent relevant to this.

[19:57:36]

* DanC frowns

[19:57:38] nmg

most details on that, danc?

[19:58:04] nmg

s/most/more/

[19:58:43] nmg

jimh: given IP situation, must et clarification on situation before we go further

[19:58:56] nmg

jimh: chartered as royalty-free

[19:59:12] DeborahMcGuinness-SWWS

some info on patents:

[19:59:13] nmg

ACTION: pfps to determin status of IP on this issue

[19:59:13] DeborahMcGuinness-SWWS

US Patent: 5720008: McGuinness, Patel-Schneider, and Resnick. "Knowledge Base Management System with Dependency Information for Procedural Tests", Issued 2/17/98, Submitted 5/94.

[19:59:13] DeborahMcGuinness-SWWS

US Patent 5974405: McGuinness, Patel-Schneider, and Resnick. "Knowledge Base Management System with Enhanced Explanation of Derived Information", Issued 10/26/99, submitted 5/94.

[19:59:19] nmg

thanks

[20:01:08] nmg

POLL: ignoring IP issue, service for providing instance data (one third each way)

[20:03:42] nmg

pfps: (re: consistency checking of instance data) wrt classification of instance data

[20:04:32] DeborahMcGuinness-SWWS

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[20:06:36] nmg

jjc: propose vote on decidability of contstraint checking

[20:07:26] nmg

POLL: Constraints checking: Given a large amount of instance data, it should

[20:07:26] nmg

be possible to check if the instance data confers to a given ontology

[20:08:25] nmg

(split between in favour and don't care, some opposed)

[20:08:50] nmg

jimh: needs to be revisited, further discussion

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[20:15:44] nmg

====== General Requirements (Jeff Heflin)

[20:15:54] nmg

http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/0062.html

[20:22:00] nmg

jeffh: R1: shared ontologies - already effectively voted on?

[20:25:46] nmg

danc: (re: ontology extension) daml:imports mechanism is worth having. difference between using someone else's terms, and agreeing with all of their defns

[20:26:59] nmg

jimh: explicit mechanism for local vs global imports

[20:27:12] nmg

fvh: large open isse

[20:28:05] nmg

jimh: needs further discussion

[20:30:29] nmg

jeffh: (re: ontology evolution) rdfs recommends using subClassOf for denoting evolution of terms

[20:30:47] nmg

jjc: RDF Schema spec still under discussion

[20:31:24] nmg

ACTION: jeffh to bring implications of this use of subClassOf to attn of RDF Core WG

[20:32:19] nmg

danc: expect this functionality from rules layer, not from ontology layer

[20:32:27] nmg

chair passes to las

[20:32:39] nmg

jimh: this belongs in ontology layer

[20:33:34] nmg

jimh: straightforward starting place for managing versioning in ontologies (paper by jimh and jeffh)

[20:33:37] nmg

pointer to the paper?

[20:34:48] nmg

ontologies reflect social consensus, which changes. ontologies are not static

[20:35:08] nmg

las: take vote on versioning - postponed before

[20:36:22] nmg

POLL: versioning should be requirement for language (mostly in favour, few opposed, few don't care)

[20:36:29] nmg

chair returns to jimh

[20:37:36] nmg

jeffh: (re: ontology interoperability) mapping here is not rule-based

[20:37:59]

* las hopes we have time for the semantics discussion before she has to go catch her cab....

[20:39:21] nmg

POLL: saubclass/superclass, inverse, equivalence (all in favour)

[20:39:52] nmg

jimh: complex extensions - implication off the table, procedural attachment dealt with elsewhere

[20:40:32] nmg

POLL: complex extensions (mostly against, one in favour, few don't know)

[20:41:10] DanC

note that this poll was in the context of "ontology interoperability" i.e. mapping

[20:41:58] nmg

jimh: (re: R5 detect inconsistency) tabled previously for future discussion

[20:42:14] nmg

danc: need time for future discussion, ideally

[20:43:17] DanC

what I wanted to say is: it's ok to postpone discussion of the decidability requirement for a time, but I hope to get back to it within this ftf meeting

[20:43:32] nmg

sorry - thanks for the clarification

[20:45:03] nmg

fvh: (re: R6 scalability) complexity of reasoning depends on complex DL class defns (as opposed to class use by name in frame systems)

[20:45:57] nmg

(ie. complex defns of unnamed classes)

[20:46:11] nmg

ianh: not necessarily the case

[20:46:24] nmg

jimh: table for future discussion tomorrow

[20:48:17] nmg

jeff: (re: R7 ease of use) feature or design goal?

[20:48:30] nmg

jeffh: no specifics for this

[20:48:46] nmg

jeffh: table XML syntax for future discussion

[20:48:47] DanC

hmm... it does seem useful for our requirements document to say something about the context, i.e.: The Web is Big.

[20:49:13] nmg

jeffh: ditto R9, R10

[20:50:58] nmg

dmcg: (re: C1 explainability) justification for statements in language (cf. proof checking)

[20:51:28] nmg

jjc: (re: C2 i18n) would like this to be a requirement

[20:51:44]

* DanC realizes he just admitted to not reading all the meeting materials. oops.

[20:51:44] nmg

====== jeffh finishes

[20:53:31] nmg

jimh: follow-on work for each group - reduce to a couple of use cases, choose writers for such

[20:54:21] nmg

jimh: language features from use case groups

[20:54:39] nmg

jimh: design goals from general requirements group

[20:57:37] nmg

====== session ends

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[21:07:06] heflin

Here's the URL for the paper on versioning:

[21:07:09] heflin

http://www.cse.lehigh.edu/~heflin/pubs/#aaai2000

[21:07:36] heflin

There's also more detail in chapter 3 of my thesis:

[21:07:56] heflin

http://www.cse.lehigh.edu/~heflin/pubs/#heflin-thesis

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[21:17:41] nmg

====== OWL Discussion (Peter Patel-Schneider)

[21:20:45] nmg

tim: (re: representation horror stories) what about the success stories?

[21:20:59] nmg

pfps: relational databases - good theoretical basis

[21:21:49] nmg

pfps: programming languages such as ML

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[21:24:30]

* las is not sure how to be interpreting this presentation. I feel like Peter is stating as fact(oid) things that are simply not.

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[21:25:07] las

E.g., there *is* grounding for the web.

[21:25:56] DanC

is there a quick answer to "what's the difference between ZF set theory and flat set theory?"

[21:25:56] nmg

pfps: axiomatisation is a (slight) cheat - grounds out in another proof or model thoery

[21:26:17] nmg

(not-scribe) answers on a postcard

[21:26:56] nmg

pfps: ideally, you have *all* of the above - proof theory, model theory, axiomatisation and operational theory

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[21:28:18] nmg

jimh: other formalisations - possible world semantics

[21:28:33] nmg

pfps: possible worlds (kripke) similar to model theory

[21:29:53] nmg

pfps: intuitions re: formalisations not necessarily correct - cf. (early, flat) set theory

[21:30:16] nmg

pfps: zf set theory is believed to be correct

[21:30:50] DanC

http://www-db.research.bell-labs.com/user/pfps/talks/

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[21:31:13] sandro

thanks.

[21:31:34]

* DanC wonders what the problem with DAML+OIL entailment is

[21:32:12]

* las thinks Peter means that he can't write a semantics that agrees with RDFS semantics and that doesn't have a paradox.

[21:32:13] nmg

pfps: incosistency/paradoxes are one problem, but formalisation may not be right in a more subtle way

[21:32:20] nmg

pfps: ie. daml+oil entailment

[21:32:25] sandro

[ Why does Pat Hayes say RDF has published semantics? Does he view M&S as actually presenting the semantics of RDF? Or does he view his model theory as normative? ]

[21:33:24]

* DanC isn't at all sure that "we have all seen Russell's paradox"

[21:34:54] nmg

pfps: intuitionist logic rejects 'contradiction implies everything', relevantistic logic (sp?) makes a stronger statement

[21:36:43] sandro

can someone throw in an occastional slide number?

[21:36:53]

* nmg hopes someone has a camera to capture this diagram

[21:37:08] nmg

slide 13

[21:38:11] nmg

pfps: once commitment is made to syntax and semantics for a representation language, cannot change either

[21:38:51] nmg

pfps: need to decide relationship (in terms of syntax, smenatics and expressive power) between OWL and RDF(S) and XML

[21:41:25] DanC

lynn's point is a good one... relationships between systems include not just "the same" inferences, but S1 sound wr.t. S2 or S1 complete w.r.t S2.

[21:42:00] nmg

las: soundness and completeness refer to relationship between systems

[21:42:27] las

S1 sound wrt S2: If S1 says it's so, S2 agrees. S2 complete wrt S1: If S2 says it's so, S1 agrees.

[21:42:46] DanC

RDFS is complete w.r.t RDF, but not sound.

[21:43:03] nmg

pfps: rdf and rdfs have same syntax and semantics - rdfs complete wrt to rdf, not sound

[21:43:26] DanC

I want OWL to be complete w.r.t. RDFS but not sound.

[21:43:54] nmg

pfps: unsoundness does not mean that you can draw contradictory consequences, only that you can draw more

[21:43:54] las

Specifically, consequential closure of RDF is a subset of RDFS

[21:45:00] nmg

pfps: relationship between rdf and xml - uses xml syntax, ignores xml semantics

[21:45:02] DanC

PFPS: RDF syntax is a subset of XML syntax. RDF semantics are pretty much unrelated to XML semantics.

[21:46:36] las

Oh, also, there's soundness on a subset. E.g., the propositional subset of FOPC is sound wrt propositional calculus, and RDFS's RDF subset is sound wrt RDF (duh)

[21:46:39] nmg

pfps: XML is mapped into a tree (by XML Infoset or XML Query), RDF graph does not correspond

[21:46:45] sandro

"ignores xml semantics" Actually no -- XML has several common semantic forms (see H. Thompson's paper) and RDF/XML basically lets you use each of them, while indicating which you are using so it can all be understood.

[21:47:00] nmg

pointer for the paper?

[21:47:05] sandro

looking

[21:47:42] sandro

http://www.ltg.ed.ac.uk/~ht/normalForms.html

[21:48:46] nmg

pfps: two (different) defns of OWL - OWL, and OWL'

[21:48:59] sandro

But yes -- it is not directly related to the infoset semantics -- it's about the intended semantics of the authors.

[21:49:32] nmg

http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/0042.html

[21:51:23] nmg

pfps: OWL' much like DAML+OIL, slightly different syntax (slide 15)

[21:54:22] nmg

pfps: anti-foundation avoids some paradoxes, but at a cost (classes not referring to themselves)

[21:55:44] nmg

pfps: model theory based of zf set theory avoids russell's paradox, regardless of foundation axiom

[21:56:37] nmg

url for russell's paradox

[21:56:56] nmg

http://plato.stanford.edu/entries/russell-paradox/

[21:58:33] nmg

pfps: contributing to problems/paradoxes: meta-model (rdf:Class in the model), negation, entailment

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[21:58:52] nmg

pfps: removing one of these avoids problem

[21:59:02] jdale

and for the liar's paradox, see: http://www.utm.edu/research/iep/p/par-liar.htm

[21:59:03] nmg

pfps: rdf/s removes negation

[21:59:22] nmg

pfps: daml+oil removes entailment

[22:00:13] nmg

pfps: clarification - daml+oil does not do *rdf* entailment

[22:00:16] Jah-wowg

remove RDF model of entailment

[22:01:09] nmg

jimh: daml+oil has no negation

[22:01:18] nmg

danc: complementOf is a form of negation

[22:01:32] Jah-wowg

no - I said DAML+OIL doesn't have full logical negation (i.e. NOT)

[22:01:50] DanC

russel set in DAML+OIL: "the class of things that have no rdf:types that ...". hmm... missed part of it

[22:01:59] nmg

sorry

[22:02:13] las

pfps: you can construct a Russell-like property by building the class of things that are not the RDF type of anything.

[22:02:49] DanC

http://www-db.research.bell-labs.com/user/pfps/talks/webont-f2f-owl/slide25-0.html

[22:03:07] DanC

check that out, sandro. I'm gonna try to translate to N3 (and maybe to KIF)...

[22:03:54] DanC

I'm quite interested in paraconsistent logics.

[22:04:45] las

Logic families Peter doesn't want to consider: intuitionistic, relativistic, paraconsistent.

[22:05:12] las

Also 3-valued and stratified, but I'm with him on those (although stratified isn't totally out of the question).

[22:05:33] nmg

http://www-db.research.bell-labs.com/user/pfps/talks/webont-f2f-owl/slide24-0.html

[22:05:42] DanC

[[[

[22:05:45] DanC

this <http://www.w3.org/2000/10/swap/log#forSome> :_g1 .

[22:05:46] DanC

[22:05:46] DanC

:_g1 a :_g1,

[22:05:46] DanC

owl:Restriction;

[22:05:46] DanC

owl:hasClassQ [

[22:05:46] DanC

owl:oneOf [

[22:05:48] DanC

owl:first :_g1;

[22:05:50] DanC

owl:rest owl:nil ] ];

[22:05:52] DanC

owl:maxCardinalityQ "0";

[22:05:55] DanC

owl:onProperty rdf:type .

[22:05:57] DanC

]]]

[22:06:42] las

This (Does John belong to the intersection of student/not student) is a nice example....it doesn't support reasoning by cases. Really, it's RBC, not LEM (law of the excluded middle) that will cause us the most problem....

[22:10:00] nmg

pfps: classes with reflective defns are not all problematic, but the dividing line between those that are and those that aren't is not simple

[22:10:16] las

RBC=reasoning by cases. (If a, then.... If not a, then....)

[22:12:20]

* sandro has too-little experience with daml:restrictions to be much use here.

[22:12:54] nmg

pfps: (re: avoiding paradoxes without throwing out one of negation, entailment and the metamodel) adopt an extended syntax for restrictions

[22:13:21] DanC

==== daml+oil version of russel's paradox, rendered in KIF

[22:13:23] DanC

(prefix-kludge "owl" "http://example/owl-vocab#")

[22:13:23] DanC

(prefix-kludge "rdf" "http://www.w3.org/1999/02/22-rdf-syntax-ns#")

[22:13:23] DanC

(exists (?1_1 ?2_2 ?3_3 )

[22:13:23] DanC

(and

[22:13:23] DanC

(rdf:type ?1_1 owl:Restriction )

[22:13:24] DanC

(owl:onProperty ?1_1 rdf:type )

[22:13:26] DanC

(owl:maxCardinalityQ ?1_1 "0")

[22:13:28] DanC

(owl:hasClassQ ?1_1 ?2_2 )

[22:13:30] DanC

(owl:oneOf ?2_2 ?3_3 )

[22:13:32] DanC

(owl:first ?3_3 ?1_1 )

[22:13:33] nmg

las: tradeoffs in whatever decision we take, but have tradeoffs been discarded out of hand?

[22:13:34] DanC

(owl:rest ?3_3 owl:nil )

[22:13:36] DanC

(rdf:type ?1_1 ?1_1 )

[22:13:38] DanC

)

[22:13:40] DanC

)

[22:13:42] DanC

====

[22:14:04] nmg

danc: reading pfps' 'we can't' as 'i'd rather not'

[22:14:29] nmg

pfps: not the case

[22:15:07] nmg

dieter: problem arrives when you assume that model theory of owl will be a monotonic extension of that of rdf

[22:15:42] nmg

fvh: price of not writing restrictions as rdf?

[22:15:50] nmg

pfps: can't query *about* restrictions

[22:16:01]

* las very much regrets that I need to pack up any minute....I really don't want to miss my cab or my flight....

[22:16:03] nmg

pfps: can define classes in terms of restrictions, however

[22:16:16] nmg

pfps: query wrt those

[22:16:22]

* DanC regrets that too. sigh. logistics are such a bummer.

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[22:18:07] nmg

las: socratic approach?

[22:19:01] las

Reference: Jim Crawford (Ben Kuipers), Algernon. Sorry, my browser is closed and I can't find a pointer, but there was a AAAI paper and a UT Austin thesis.

[22:19:10] nmg

thanks

[22:20:01] nmg

http://citeseer.nj.nec.com/crawford91algernon.html

[22:20:11] las

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[22:20:39] DeborahMcGuinness

here is one pointer

[22:20:39] DanC

we haven't explored the cost of throwing out (various forms of) negation, to my satisfaction.

[22:20:41] DeborahMcGuinness

http://www.cs.utexas.edu/users/qr/algernon.html

[22:20:43] nmg

http://www.cirl.uoregon.edu/crawford/papers/algy_sigart.ps

[22:21:34] DanC

I find intuitionistic/constructionist logics most promising. i.e. throwing out negation in a way, or throwing out entailment in a way. i.e. making proof harder.

[22:22:31] nmg

las: would socratic querying tamper with entailment

[22:22:33] nmg

pfps: pfps

[22:22:36] nmg

pfps: yes

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[22:23:55] nmg

====== session ends

[22:24:07] DanC

logger, pointer?

[22:24:07] DanC

See http://ilrt.org/discovery/chatlogs/webont/2002-01-14#T22-24-07

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[22:25:44] DeborahMcGuinness

and DAML+OIL (March 2001): A Datatype Extension to DAML+OIL (December 2000)

[22:25:44] DeborahMcGuinness

Feedback to www-rdf-logic, please.

[22:25:44] DeborahMcGuinness

DAML+OIL (March 2001) version (revision 4.1): Ian Horrocks, Frank van Harmelen and Peter Patel-Schneider, editors.

[22:25:44] DeborahMcGuinness

The idea behind DAML+OIL (March 2001) is to extend DAML+OIL (December 2000) with arbitrary datatypes from the XML Schema type system (http://www.w3.org/TR/xmlschema-2/#typesystem), while still retaining the desirable properties of the ontology language, in particular its (relative) simplicity and its well defined semantics. This is achieved by maintaining a clear separation between instances of "object" classes (those defined using our ontology languag

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