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W3C Rules Interchange Format Basic Logic Dialect

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Presentation on theme: "W3C Rules Interchange Format Basic Logic Dialect"— Presentation transcript:

1 W3C Rules Interchange Format Basic Logic Dialect
Chris Welty IBM Research & RIF WG co-Chair

2 Rules, rules, rules…

3 The Web Standards

4 Semantic Web Layer Cake V1

5 Semantic Web Layer Cake Vpast
Trust Proof Signature Logic Rules OWL RDFS RDF IRI/Unicode

6 Semantic Web Layer Cake Vpresent
Rules Trust Standards Proof Signature Encryption Logic Framework SPARQL OWL Rules Rules RDFS RDFS RDF IRI/Unicode

7 RIF Background Semantic web approach The OWL WG approach
interoperability requires a formal semantics The OWL WG approach Start with something (DAML+OIL) Literally hundreds of rule system implementations JSR-94, ISO-Prolog, CLIPS, OPS… Already several “SW” rule languages SWRL, RuleML, WRL, SWSL, KAON2, TRIPLE, JenaRules… Everyone wants “their” system/technique/theory to be the SW rule standard Workshop April ‘05 Outcome: Nash Equilibrium…

8 Wherefore the RIFt(s)? OWL DL < OWL < FOL
Original idea to add full first-order at the logic level Semantic web very “open world” Most back-end DBs support closed queries Many rule systems have non-FO features CWA/NAF Procedural Attachment Rule ordering Non-monotonicity … can’t be layered on OWL Not a strict SW layering already OWL restricted dialects (DL) not layered on (all of) RDF/S semantics RDF & RDFS not layered at all

9 Enter the Vendors “Rule systems Vendors” Database vendors
$1B/year existing market iLog, Fair Isaac, Haley, … Database vendors Oracle, IBM OMG PRR effort Simple production rules Event-condition-action Vendors understand the value of standardization Interchange already a priority …a common semantics?

10 “One must understand, [rule systems] include a version of negation that is operationally well-defined. The problem is to make semantic sense of it.” Fitting, 1999

11 Approach 1 Define a super-language so expressive that any language can be translated to/from it The CL and IKL approach @deprecated: infeasible for this group, as major differences appeared irreconcilable (e.g. non-mon vs. mon)

12 Approach 2 Define a core language that accounts for the intersection of all rule language capabilities E.g. Horn, datalog, … @postponed: The production rule, logic programming, and FO core is not clear

13 Approach 3 Define a logic-based core and a separate production-rule core. If there is an intersection, define the common core (which may possibly be just a syntax) @version: 0.1 BLD

14 Approach 3a Define a framework in the form of a menu of syntactic and semantic features that can be combined into dialects @version (FLD)

15 Credits BLD Editors Active WG members WG Team
Michael Kifer (U. Stonybrook), Harold Boley (NRCC) Active WG members Adrian Paschke (REWERSE), Axel Polleres (DERI), Dave Reynolds (HP), Gary Hallmark (ORACLE), Hassan Aït-Kaci (ILOG), Igor Mozetic (JFI), John Hall (OMG), Jos de Bruijn (FUB), Leora Morgenstern (IBM), Mike Dean (SRI), and Stella Mitchell (IBM) WG Team Chris Welty (IBM), Christian de Sainte Marie (ILOG), and Sandro Hawke (W3C/MIT)

16 BLD Overview Definite Horn rules
Disjunction of atoms with exactly one positive literal Equality, functions, and a standard first-order semantics Syntactic features objects and frames internationalized resource identifiers (IRIs) as identifiers XML Schema data types and builtins XML (1.0) syntax with normative XMLS definition Non-normative presentation syntax Metadata and imports

17 Symbols Used to identify constants, variables, functions, predicates
"literal"^^<symspace-identifier> Notable symbol spaces: xsd:string, rif:local, rif:iri “Chris”^^<xsd:string> “http://www.w3.org/1999/02/22-rdf-syntax-ns#type”^^<rif:iri> “Person1”^^rif:local

18 Rules IF <condition> THEN <conclusion> BLD rule:
<condition> aka rule body, antecedant <conclusion> aka rule head, consquent BLD rule: (Forall var* <conclusion> :- <condition>) Conclusions may contain conjunction Conditions may contain conjunction, disjunction, and existential Restrictions on conclusion No existential, disjunction, external functions

19 Horn Extensions Functions and external calls
Equality (in conclusion and condition) Frames Objects with slots and values Special syntactic treatment of type and subclass Named argument functions and predicates However all arguments must be provided

20 Structure Rules occur in Groups Groups occur in Documents
Group( (Forall ?x _Q(?x) :- _P(?x)) (Forall ?x _Q(?x) :- _R(?x)) ) Groups occur in Documents Document( Group((Forall ?x _Q(?x) :- _P(?x)) (Forall ?x _Q(?x) :- _R(?x))) Group((Forall ?y _R(?y) :- ex:op(?y))))

21 Simple Example Database mapping
Document( Prefix(dbp Prefix(my Prefix(rdfs Group ( Forall ?mname ?aname ?movie ?actor  my:actorIn(?aname ?mname) :- And( dbp:starring(?movie ?actor) rdfs:label(?movie ?mname) rdfs:label(?actor ?aname))))

22 Simple Example w/ Frames Database mapping
Document( Prefix(dbp Prefix(my Prefix(rdfs Group ( Forall ?mname ?aname ?movie ?actor  my:actorIn(?aname ?mname) :- And(?movie[dbp:starring -> ?actor rdfs:label -> ?mname] ?actor[rdfs:label ?aname])))

23 Named Arguments Document( Prefix(dbp http://dbpedia.org/property/)
Prefix(my Prefix(rdfs Group ( Forall ?mname ?aname ?movie ?actor  my:actorIn(actor->?aname movie->?mname) :- And(?movie[dbp:starring -> ?actor rdfs:label -> ?mname] ?actor[rdfs:lasbel ?aname])))

24 XML Syntax And (Exists ?Buyer (cpt:purchase(?Buyer ?Seller
cpt:book(?Author bks:LeRif) curr:USD(49))) ?Seller=?Author ) <And><formula><Exists><declare><Var>Buyer</Var></declare> <formula><Atom><op><Const type="&rif;iri">&cpt;purchase</Const></op> <args ordered="yes"><Var>Buyer</Var> <Var>Seller</Var> <Expr><op><Const type="&rif;iri">&cpt;book</Const></op> <args ordered="yes"> <Var>Author</Var> <Const type="&rif;iri">&bks;LeRif</Const></args> </Expr> <Expr><op><Const type="&rif;iri">&curr;USD</Const></op> <Const type="&xsd;integer">49</Const></args> </args> </Atom></formula> </Exists></formula> <formula><Equal> <side><Var>Seller</Var></side> <side><Var>Author</Var></side> </Equal></formula> </And>

25 Metadata <And> <formula>...</formula> </And>
Can hang off any “class element” <And> <meta> <Frame> <object><Const type="rif:local">pd</Const></object> <slot ordered="yes"> <Const type="&rif;iri">&dc;publisher</Const> <Const type="&rif;iri">&w3;W3C</Const> </slot> </Frame> </meta> <formula>...</formula> </And>

26 Metadata <Group> ... </Group>
Can hang off any “class element” <Group> <meta> <Frame> <object><Const type="rif:local">pd</Const></object> <slot ordered="yes"> <Const type="&rif;iri">&dc;publisher</Const> <Const type="&rif;iri">&w3;W3C</Const> </slot> </Frame> </meta> ... </Group>

27 Metadata <Document> ... </Document>
Can hang off any “class element” <Document> <meta> <Frame> <object><Const type="rif:local">pd</Const></object> <slot ordered="yes"> <Const type="&rif;iri">&dc;publisher</Const> <Const type="&rif;iri">&w3;W3C</Const> </slot> </Frame> </meta> ... </Document>

28 Status RIF BLD to Last Call June 23 RIF RDF&OWL to Last Call June 23
Last call indicates “final version for external review” w3.org/2005/rules


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