See also: IRC log
<ChrisW> list agenda
<ChrisW> scribe: Hassan
<ChrisW> scribenick: Hassan
Objections to last week minutes?
<Harold> Did we approve the f2f6 minutes?
Next telecon August 7 Poll
<LeoraMorgenstern> I can be here.
<sandro> +1 plan to be here Aug 7
+1 plan to be here (hak)
<LeoraMorgenstern> +1 to the 14th
<sandro> +1 plan to be here Aug 14
<sandro> +1 aug 21
<GaryHallmark> +1 for 21/8
<sandro> +1 Aug 28
<DaveReynolds> + 0.5
<AxelPolleres> 14th -1, 21 +1, 28 +1
Chairs will discuss the schdule for Aug telecons and will get back to the rest
Action 332 ?
Dave Reylnolds - has to do with classification.
Action 332 complete
Action 329 on ChrisW complete
Action 324 - continued
<josb> must be CTIC
F2F meetings - open actions
See wiki page
<AxelPolleres> is the date now fix?
W3C tech plenary week of Nov 6 - give opportunity to RIF to attend?
We should decide by Sept ... ?
Sandro is confused about the dates ...
<sandro> I am not at all confused about the dates.
ChrisW: What value is it to have two meetings a month apart?
Sandro: need time to work on what
to show in November
... we need a quorum for decisions
<Harold> F2F7 was pushed further and further into late Aug., then Sept.
<sandro> It's not about quorum -- it's about not excluding people.
ChrisW: the F2F will assign actions - decisions will be made by telecon
<AxelPolleres> 2 subsequent meetings in US, difficult -1
ChrisW: anyone having things to say on this issue?
<Harold> Can a F2F be replaced with a highbandwidth2highbandwidth video conference?
<DaveReynolds> If it would be useful but I couldn't guarantee to be there
Hearing none ...
ChrisW: moving to Liaisons
Report on liaisons?
Nothing on liaison
331 on Chris - on mappings?
Action 330 on Dave - done
Action 330 kept open until discussed?
Action 300 is kept open for discussion
Action 328 continued (on Sandro)
Action 328 continued (on Sandro) on XML Schema Generation new date
Action 322 on Dave is completed
Action 300-301 done
ChrisW - no more action to review
Having the sort discussion and the frame classification discussion or the RDF?
Michael being asked his reaction to the mail discussion on the subject
Michael summing up: we need a minimalistic model of class hierarchies for RIF
This will allow users using RIF for exchange to "hook" their models onto that of RIF's
This will preclude n^2 model exchange models
ChrisW: some existing for the SW - why reinvnet a new one? or why complicate the mapping from/to RDF
Jos: RDF is close - but OWL is
different (has extensional semantics ...)
... this proposal does not unify these views
MK: RDFS is a superset of that of RIF - so easy to extend
<ChrisW> ^existentials^extensional semantics^
MK: RIF class model is minimal in that it is easy to map onto all others
Jos: need additional axioms...
MK: no need
Jos: does this not imply a restriction?
MK: no ... RDF maps into RIF very naturally without problem
Dave: issues on scoping
MK: Scope for inference - what rules are visible
<Harold> Chris, since the Interop WS we have discussed a scope/module construct for rules, especially for scoped naf.
MK: classes and modules are
... no modules yet - but we are looking ahead
... want to avoid unintended interactions between imported KBs
ChrisW: let us focus on subclassing not on modules
<Harold> A scope/module is a 'local' ruleset, possibly named (as in RDF's named graphs).
<MichaelKifer> yes, the notion of modules/scopes is a generalization of rdf's named graphs
Dave: there are differences that
may conflict among different models of inheritance
... second point - how much "subclass semantics" is there in RIF?
... I thought of RIF as a blank substrate but it does not look like it is any more
MK: there is still work to do on the specs
ChrisW: try to find the most
general axioms of subclassing
... issue - why invent a new class model for semantic web?
MK: none of the existing model is minimalistic
We need a model that can be a core on most
MK: minimal in the number of axioms
ChrisW: what about OWL-DL?
MK: It has additional axioms
(such as extensionality, ...)
... the minimal axioms need to be made explicit
Gary has a question - how do we express having no subclass?
MK: this is NAF
... this a meta statement that needs something like NAF
Dave - Gary: how can you have this in the head of a rule?
Dave - cannot change the type hierarchy dynamically
Dave - unless having meta model that allows you to
MK: maybe not an issue - e.g., interfacing with Java
<GaryHallmark> for Java data model, no membership or subclass relations in rule heads
Dave: need to assume the "right" set of axioms needed for the task
<GaryHallmark> XML schema data model has similar issues to Java
Sandro: it sounds like "minimal" means underspecified or ambiguous - if so that may be an interop problem
<josb> minimal subset of RDFS, which probably gives us all we need: http://www.eswc2007.org/pdf/eswc07-munoz.pdf
Sandro: expectations may be thwarted
MK: just transitivity of subclassing is enough
<sandro> MK: B subClassof A
MK: we do need inheritance of "structure" in RIF because we have no "structure" in RIF
<sandro> Okay -- I think I understand what Michael is saying now, about how RDF doesn't have inheritance. Just inheritance of the type -- not of the properties, etc.
ChrisW: what do you mean by structure?
MK: RDF has structure (slots ...)
which is inherited
... Sorry - RDF has no inheritance
<sandro> so.... are # and ## proposed to be exactly the same as rdf:type and rdfs:subClassOf ?
<sandro> Chris: similar to RDF, except that relation itself is not in the domain.
<AxelPolleres> Summary: transitivity of subclassing and of classmembership over the class hierarchy is the minimal semantics, yes? No more need to debate (for RIF) about additional axioms/inheritance notions.
ChrisW: minimal semantics of RIF subclass has not notion of structural inheritance
<AxelPolleres> reflexive, you mean?
<sandro> jos: If you restrict the syntax of RDF, you get something the same, except that the subclassof is reflexive. In RDFS if you know A is a class, then you know A is a subclass of itself.
Jos: RDFS subclassing is reflexive
<sandro> MK: That bit of RDF has been criticized and has no justification.
<sandro> (I'm comfortable with Jos's answer)
MK: adopting RDF as a model will entail adopting relations and we do not want to do that
Jos: why not use the core that already exists
MK: because we need to differentiate the RIF from any client models
<AxelPolleres> That would bring us back to the extensibility discussion, ie. whether "restricting" a dialect is covered by "extensibility".... or no?
<AxelPolleres> ... was referring to the comment that Gary's language would need restrictions to fit into BLD.
MK: why standardize things that many do not use and "impose" it on all
ChrisW: Are logic languages conform to this approach - can they be mapped to the minimal model?
MK: They will be translated to
something else - not RDF
... they will have to map to different relations
ChrisW: is there really a
... there are 2 aspects of RDFS subclass model missing from the RIF subclass model
... (1) syntactic reflection and (2) subclassing is reflexive
<DaveReynolds> It's in OWL
Allen: what about antisymmetry?
Jos - not in RDFS.
ChrisW - it is so in OWL-DL.
MK: these differences justify taking a miminal model of subclassing
ChrisW: those arguments in favor OO models in too early - keep in mind logic languages
<sandro> Chris: These differences between the proposed RIF Subclass and RDF Subclass .... RIF having a new, more minimal one, ... does this make sense?
Jos thinks the difference between RDFS/RIF subclass model is is not sufficient justification for introducing a classification vocabulary in RIF
Dave - having no issue except that could be even more minimal
<sandro> DaveReynolds: The question is what this stuff buys us -- why should it be in BLD at all? Just define the relation yourself, if you need it, when writing/translating the rule.
ChrisW: we seem to understand
this issue better - move on ...
... any comment on this thread?
Igor: it would be good to have a resolution
ChrisW: good point -
Gary: I like the current proposal - except that we could fix it a bit for what we need
<josb> Gary, you might as well use RDFS
<josb> in both cases you need the same kind of restrictions
<sandro> Straw poll on each question....
ChrisW: (1) do we have a subclass op or (2) not
<sandro> +1 have subclass operator (instead of each one define their own mapping)
<IgorMozetic> +1 for subclass
<AllenGinsberg> +1 (only if extensible)
<GaryHallmark> josb: I'd need to see some kind of a proposal before I could agree
<sandro> MK say +1, not on IRC
<AxelPolleres> +1 subclass (as syntactic sugar foe a ruleset emulating the semantics of RDFS, basically)
Jos: does not understand the question
<josb> Gary, if you could send me a link to a use case, I can try to show how to use RDFS in this case
Axel: RDFS semantics can be emulated through ruleset?
<josb> In any Datalog-like language
MK: yes - it can be
<sandro> Axel: since RDFS can be expressed (emulated) as a BLD ruleset, then we can see this proposal for a syntactic construct of subclass, then this gives you an automatic inclusion of part of the RDFS ruleset.
<sandro> MK: I understand Axel to be supporting my proposal.
MK: Axel's point is in agreement with my proposal
<josb> My problem is that I need the additional constructs
MK and Axel argue a technical point ...
Nobody undertands ... :-)
<sandro> Axel -- what Sandro said is what I meant.
<AxelPolleres> yes, with emphasis on *part of* the RDFS ruleset.
<sandro> Axel: What MK wants is the same subset of RDFS that I have in mind.
<josb> reflexivity is the difference
MK and Axel: argue subclass operator in RIF and RDFS
<AxelPolleres> probably yes.
ChrisW: will summaruze in email
<sandro> AxelPolleres, can you write the rules you have in mind, and send them in e-mail?
This is scribe.perl Revision: 1.128 of Date: 2007/02/23 21:38:13[End of scribe.perl diagnostic output]
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