Chris: This discussion is to review the current RIFRAF discriminators proposed by Harold and make sure we understand them.
terminating vs. non-terminating rule-bases, discriminator on language?
Harold: part of language (or given KB in language)
csma: is it possible to write rule-bases such that some queries do not terminate?
Harold: prohibit from language non-terminating queries, or prohibit recursion
csma: Feature of rule-base, not language?
Piero: Feature of semantics, i.e. semantic discrimintor
Hassan: discriminiator on rule set
Piero: Object to consider termination as discriminator of language, more aspects
Harold: examples where termination needs to be guaranteed
... discriminator needs rewording
... Does the language allow to express non-terminating queries (as annotations)
Chris: But that's not a discriminator of the language
chris: remove rulebases from semantic discriminator 1
Piero: property of termination is a collective combination of language, rules base, inference engine, ...
<sandro> gary: a rule engine that didn't terminate for a terminating language is a bug
Piero: termination of a language depends on evaluation (e.g. bottom-up vs. top-down)
<sandro> Piero: top-down might be the right thing.
Piero: objects to 1 as discriminator on language (even if "rulebase" omitted)
<sandro> Jos: "The problem of ground entailment is Decidable" is a good phrasing.
josB: add "real" semantic discriminators
Turing complete is a property of expressiveness
chris: decidable vs non-decidable, Turing vs. Non-Turing complete as semantic discriminators
... 1st Turing ...
<scribe> New number 2: decidable ...
josb: have discriminator "expressiveness" (that can be Turing complete etc.)
PaulV: Why are these discriminators useful?
chris: apply discriminators to different systems, different dialects
<scribe> New: 1. Turing-complete vs. non ...
<scribe> New 2: Decidability
<josb> 3. finite-model property
Harold/chris: delete old "4" (modality ...)
chris: keep modality, skip intentionality
... add operational, declarative semantics as discriminator?
sandro: not property of language, but of language specification
Piero: is property of program
Agreement: operational/declarative semantics NOT added
Axel: How to account for describing under which circumstances a system terminates?
Piero: inference control not a discriminator of the language
Human annotation of rule sets or inherent discriminator of rule sets?
<sandro> Chris: If you have a language which HAS inference control, then you want to be able to convey that.
Piero: distinguishe rule systems from just languages when assigning discriminators
Axel: separate discrimantors on languages vs. systems
Chris: these are discriminators on SYSTEMS
hassan: pragmatic discriminators = How systems/languages are used
dave: e.g. side-effects are part of language
Piero: Notion of "language" needs to be clarified
... Language = syn sem or syn sem pragm?
Axel: Keep "inference control", but in longer run be more precise as to language vs. system discrimantors
chris: label "pragmatic" not important
sandro: what are actions following from point "inference control"?
chris: do topics belong to RIFRAF is important, not headings
next discriminator: computational complexity
chris: granularity of complexity discriminator?
add explicit complexity categories?
Hassan: complexity preserving translations are to be guaranteed
Piero: Which operations have which complexity consequences: needs to be taken into account
... potential impact on RIF: certain languages might not be embeddable if the have certain complexities
Harold: Most rulesets can be classified according to complexity classes (see "deciabilty" topic on WIKI)
csma: question for translator/implementor not for RIF?
Harold/Piero: useful tool to classify classes of languages
chris: copy text from "above" to topic comp. complexity
next discriminator: interoperabilty
<sandro> 3.1. Annotations
Harold: Annotations means comments, e.g. in controlled English
3.1 annotations accepted as discrim
3.2 test cases not a discriminator?
test case is kind of annotation
<sandro> 3.2. Test Cases -- does the language allow you to say "this is a test case?"
<sandro> 3. Annotations for Interoperability
<sandro> (a kind of metadata)
chris: does language allow to attach interoperabilty information?
... syntactic sugar in one language not supported in other language, use clusters
csma: decide what to do wrt to 2nd WD
Paul: need enumeration on certain topics, e.g. complexity classes
chris: Put refined/elaborated version of discriminators in next WD
csma: need to have sth about RIFRAF in next WD
... make clear that current/refined version is work in progress
... agreement that the list makes sense "in principle"
... list should be edited/commented/detailed, e.g. by Gary?
chris: reconcile list with requirements needed
Who is taking action?
chris: identify/refine new discriminators
sandro: stick to phase I discriminators
csma: two questions: what to do wrt to next WD AND what to do in the longer run
annotate existing discriminators wrt to phase 1 and phase 2
Hassan: put all discr. in next WD, but annotate according to phase
concrete proposal after break