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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[14:11:13] em
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* em wonders if there is a webont channel for f2f?
[14:11:34] DanC
[Lucent host]: Sheila M and I are running a workshop...
* DanC is coming from the ftf; dunno whether this channel will be "official" in any way
* 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
[14:21:17] DanC
-- Gibbins
[14:21:24] DanC
-- Dale, Fujitsu
[14:21:30] DanC
-- Jos De Roo
[14:21:36] DanC
-- 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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[14:22:08] DanC
[..] = 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.
* DanC notes that the chair did designate this channel for minutes
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[14:28:21] DanC
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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[14:31:50] tim
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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[14:35:28] tim
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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[14:38:55] tim
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
[14:54:22] DeborahMcGuinness-SWWS
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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
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[15:03:41] tim
danc: reviws schedule for rest of day
[15:04:33] tim
jimh: reviewing tomorrow's schedule
* 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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[15:38:18] DanC
======= 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?
* 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.
* 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.
* 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
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[16:48:10] DanC
hmm... is this Oiled thing OpenSource?
* 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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[18:03:19] nmg
====== 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."?
[18:11:44] DeborahMcGuinness-SWWS
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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?
[18:16:41] DeborahMcGuinness-SWWS
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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
[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
[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
[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
[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)
* 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.
* DanC frowns
[19:57:38] nmg
most details on that, danc?
[19:58:04] nmg
[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
[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
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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
[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
* 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
* 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
[21:07:36] heflin
There's also more detail in chapter 3 of my thesis:
[21:07:56] heflin
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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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* 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
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[21:31:13] sandro
* DanC wonders what the problem with DAML+OIL entailment is
* 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? ]
* 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?
* 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
[21:47:42] sandro
[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
[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
[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
[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
[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
[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
[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....)
* 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
[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
* 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
* 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
[22:20:01] nmg
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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
[22:20:43] nmg
[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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====== 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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