See also: IRC log
<ChrisW> Scribe: Hassan
Jos: update on the OWL document - things are going "smoothly" - work on on-going issues e.g. negative guards
Chris: asking what specific restriction on NGs we need to have
Jos: yes - some restrictions are
in order for it to have tractable guards
... leaning toward having such NG's
Axel: if NG's are restricted to
literal only, then they're ok.
... Both and Nega. guards need to have either T or F - nothing specified otherwise
... NG issue may become obsolete if we have LP and Neg. by failure
... would rather drop them than having this "crooked" version...
ChrisW: this WG is not designing an LP dialect
Jos: Dave wants to make the ontologies independent from the OWL/RL rule processing
Axel: Dave said that we would be ok with the limited NGs
Jos and Axel: discuss the fine differences in re. data types
ChrisW: whos feels strongly about dropping NGs altogether?
Jos: not me
<ChrisW> PROPOSED: Change all negative guards to work on the literal domain only, e.g. isNotIntegerLiteral
<ChrisW> (for next telecon)
Axel: discussing the NG uses in
... these examples need to know what ages are not integers in order for it to be able to compute the age differences
Chrisw and Hak: maybe this is a bit contrived?
Axel: we need to specify what to do otherwise ...
<josb> take any of the disjunction cases
ChrisW: still doubtful - we need a really uncontroversial example where isNotInteger is needed without question
Axel: such are common examples in Data Models fron the Net
Jos: what about the UCs involving disjunction in negative guards?
<AxelPolleres> As opposed to ChrisW's argument that the YoungParent use case was about bas data modeling... I oppose that cleaning up messy data is a perfect UC for RIF, IMO.
<AxelPolleres> One example is the use of dc:creator in RDF data which some people use with strings, others to refer to an RDF resource which is a foaf:Person with a name.
ChrisW and Jos: discussing the meaning of negated types in his examples
Axel: finds it more
... must specified when it is true/false or undetermined
<josb> isNonIntegerLiteral is false for everything that is an integer or a non-literal
<josb> isNotInteger is false for everything that is an integer
Jos: objects to Axel's proposal
<AxelPolleres> I didn't make a proposal ?!?
ChrisW: I understand what Jos is saying
Axel: I wanted to clarify things between Jos's point and alternative meanings
Jos: argues for his proposal as being sound and useful
ChrisW: I now understand the Test Case and I now think it is non contrived and a nice one
Jos: I am so happy :-)
<ChrisW> PROPOSED: Change all negative guards to return true only for literals that are not of the type, false for non-literals
<AxelPolleres> I still think that the use case is contrived for the normal user.
<josb> it's a test case, not a use case :)
Axel: discusses Jos's proposed Test Case use of Negative Disjunction in guards
ChrisW: wonders what the consequences of allowing/forbidding such guards would be
Jos: cannot force an object to be an integer
MK: why do we need NGs in BLD?
ChrisW: needed for OWL
MK: I seem to remember we discussed this earlier this year though not exactly what we discussed
<josb> DaveR is the biggest proponent
ChrisW: Next: DTB/Builtins for
... less-than or compare?
<Michael_Kifer> may be Dave could send an email explaining the issue? Certainly OWL-RL could not have been the reason back in February
... what about string less-than or compare?
... make things uniform across datatypes
Jos: who wants what?
... Objection to making the language more complex
Axel: less-than, greater-than (or equal) are now available for all types that have comparisons
Jos: make such things more generic/abstract
Axel: there is a task force
ChrisW: The Abridged Syntax TF is the one
Axel, ChrisW: discussing the choices made for having some operators but not others, redundancy, etc...
<josb> +1 against
ChrisW: Who's for the string operators?
ChrisW: Who's against the string operators?
Jos: finds them unneeded and
... I don't care dropping them if we may define them with others
Axel: can agree to leave them for now ?
Jos: I prefer dropping them now
Axel: I introduced them in because Gary asked for them - but I don't object dropping them
<ChrisW> ACTION: Chris to update ISSUE-67 to indicate discussion is postponed until the presentation syntax is finished [recorded in http://www.w3.org/2008/12/23-rif-minutes.html#action01]
<trackbot> Created ACTION-677 - Update ISSUE-67 to indicate discussion is postponed until the presentation syntax is finished [on Christopher Welty - due 2008-12-30].
Jos: I do not think Gary minds either way (but he's not here today)
<AxelPolleres> good, let's just propose to drop them next time and ask Gary for an opinion explicitly.
<AxelPolleres> "Editor's Note: It is still under discussion in the WG whether an additional predicate pred:hasNotDatatype should be added, cf. ISSUE-80."
ChrisW: Dave suggested that the OWL/RL would be considerably simpler if we had such predicates
Jos: such may be useful, but we should choose between two kinds of guards, though I slightly prefer what we have now
<ChrisW> isOfType(?x, ?type)
Axel: agrees that this would simplify and give it some parametricity
Axel: discusses elegance ...
<AxelPolleres> slight preference for onlyu having more general and get rid of guyards and neg guards as a whole.
ChrisW: I hear Jos for more generality. Axel for more specificity.
Hak: I agree with Jos
<josb> I prefer isInteger; Axel prefers isType(?x, xsd:integer)
<ChrisW> Axel: guards that take type as an arg
<ChrisW> Jos: guards that have type in the name
<AxelPolleres> my argument is for maintenance nightmare...
<AxelPolleres> ... I am for more general.
Hak:I was wrong: in fact, I agree with Axel!
<AxelPolleres> +1 to MK
ChrisW: I am hearing support for the "isType/isNotType" generic notation
<AxelPolleres> LiteralHasDatatype and LiteralHasNotDatatype
<ChrisW> PROPOSED: add isOfType and isNotOfType (based on resolution of issue-79) and remove specific type-named guards (e.g. isInteger)
Hak:I prefer ChrisW's
<josb> (i) isLiteralOfType/isLiteralNotOfType
<ChrisW> +1 shorter
<josb> (ii) isLiteralOfDatatype/isLiteralNotOfDatatype
<ChrisW> +1 i
Hak:+1 for (i)
<Harold> +1 i
<AxelPolleres> +1 for (ii), no objection to (i)
<ChrisW> PROPOSED: add isLiteralOfType and isLiteralNotOfType (based on resolution of issue-79) and remove specific type-named guards (e.g. isInteger)
Axel: what about a resolution with negative guards?
<ChrisW> PROPOSED: add isLiteralOfType and isLiteralNotOfType (based on resolution of issue-79) and remove specific type-named guards (e.g. isInteger, isNotInteger)
<AxelPolleres> does that mean I can start implementing this? :-)
Jos: What are the issues?
... Shouldn't this be datatypes?
<AxelPolleres> (BTW: we still need a RESOLVED: for the minutes, or you only want to resolve it next time?)
ChrisW: this issue then is about
... what OWL datatypes do we have to support that we do not already?
Jos: Dave had reservations about these issues (implementability)
ChrisW: Boris Motik seemed to be willing to drop some of their stuff
Jos: I did not get the same feeling
<ChrisW> We are not passing resolutions today
<ChrisW> just proposing them for next telecon
Jos: the XML schema explicitly
states that applications are free to interpret some of these
... also has a list of necessary things that implementations must support
ChrisW: has anyone listed the discrepancies between OWL/RL and RIF datatypes?
Jos: cites examples of such
Jos and ChrisW: review some weird OWL/RL datatypes ...
ChrisW: anyone on the call has an opinion of these?
<AxelPolleres:> that anyURI is a not subtype of strings is IMO kinda weird... isn't it?
Jos, ChrisW, Axel: discussing data typing in OWL/RL
Jos: a priori has no objection in re. data types except for the date/time data type
<AxelPolleres> ok, at least we have agreed on proposing some resolutions next time. :-)
ChrisW: any other discussion?
<AxelPolleres> MERRY CHRISTMAS!!!
Hak: Happy everything!