Ontology Mapping with Cyc

1. Ontology Mapping with Cyc doug foxvog 14 July 2004 http://www.cyc.com/doc/white_papers/mapping-ontologies-into-cyc_v31.pdf

2. Ontology Mapping • Completed Mapping Projects • Mapping Vocabulary • CycL Syntax and Terminology • Importation • Importation Suggests Additional Knowledge • Mapping to Less Expressive Ontology • Summary 2

3. Ontology Mapping at Cycorp • Several projects have linked external ontologies, taxonomies, and term code sets to Cyc. • Non-proprietary imported ontology projects included the mapping and/or importation of: • NAICS and UNSPSC – over 10,000 classes (industries, products) • FIPS 10-4 - 3,400 individuals (geopolitical entities) • MeSH - over 250 classes (anatomical parts) • SNOMED - over 500 classes (anatomical parts) • SENSUS - over 200 terms (mathematical & logical terms) • OpenDirectory - over 10,000 terms (website types by topic) • WordNet 1.6 - 12,000+ terms (general) • 1997 CIA World Factbook - over 5900 facts (geopolitical) • No non-proprietary ontology exports 3

4. Mapping Vocabulary • #$synonymousExternalConcept • #$overlappingExternalConcept • #$extConceptOverlapsColAndReln These specify mapping of terms by relating Cyc term to term in other ontology (#$synonymousExternalConcept ?THING ?ONTOLOGY ?STRING) (#$extConceptOverlapsColAndReln ?CLASS ?PRED ?ONTOLOGY ?STRING) . 4

5. Mapping Vocabulary #$MeaningInSystemFn • Used to express the meaning of a term in an external ontology which has not (yet) been defined in Cyc. (#$MeaningInSystemFn #$GalwayCityOntology “quayStreetGalway”) . 5

6. Contexts in Cyc • A context (#$Microtheory) is a logical world in which formulae are true/false/ unknown. • Assertions true in a context need not be true outside the context. • Each context is defined as a subcontext (using #$genlMt) of one or more contexts. • Cyc defines partial ordering of contexts via #$genlMt (a transitive predicate). • There is a universal common #$genlMt. 6

7. Context of Imported Assertions • Imported assertions are often made in a context specific to the external ontology. • This context is placed as a subcontext (using #$genlMts) to the context(s) for the type of concept which the external ontology is about. • Mapping assertions are made in separate context, if linkage to be maintained. • Imported assertions raised to more general context if appropriate. 7

8. Importation of an Ontology • Create or Match terms in Cyc to terms in ontology • Initial mapping • Translate definitional assertions to CycL • Translate non-definitional assertions to CycL • Search for matching Cyc concepts • Merge with matching Cyc concepts • Refine mapping • Assisted refinement of information 8

9. Importation of an Ontology • Specialized tools built for importation of massive databases and taxonomies (e.g., NAIC -- North American Industry Classification System) • “Slurping” tools used for standard databases • Shell/editor scripts used for tabular data • These tools provide a first pass -- generating classes, relations, individuals, & mappings, and expressing relationships specified in the source. • Phrase parsing for (proposed) names • #$isas and #$genls connect to Cyc ontology • Second pass: generality level, suggested KE. 9

10. Importation of an Ontology • If an ontology being imported has a notion that is not in Cyc, a term for that notion is normally added to the Cyc ontology. • Functional terms, using #$MeaningInSystemFn, may be created if there are no obvious direct mappings so that assertions in the external ontology can be represented. • Functional term definition may be used All x such that y #$SubcollectionWithRelation[From|To][Type]Fn • As Cyc terms are created (or discovered) with the correct meanings • The functional term is normally replaced. • A #$synonymousExternalConcept assertion is made to express the mapping. . 10

11. Special Cases #$MeaningInSystemFn term is maintained or replaced with #$overlappingExternalConcept • Predicate with different argument order • #$genlInverse (2x) for binary predicate • Use rule for higher-order predicate • New meta-predicate if becomes common • Attribute/Relation/Class/ mismatch • Use rule or meta-predicate • Term not interesting for Cyc • Poorly defined or motivated term • Special vocabulary for mapping DB schema 10

12. Importation Second Pass • Redundancy Removal • Assertion subsumed by existing more general assertion • Generality Level Checking • Should assertion be more general/specific • Options given of term replacements • Intermediate Class Suggestion • Multiple sibling classes with similar assertions • Suggested Knowledge Entering 11

13. Importation Suggests Additional Knowledge • #$requiredArg1Pred and #$requiredArg2Pred assertions suggest roles that should be asserted for instances of given types. • A number of other predicates are also used to more or less firmly suggest other assertions that should be made for instances of certain classes: During suggestion phase, the imported concept is more firmly linked to Cyc ontology. 12

14. KE Suggestion Predicates • keStrongSuggestion keGenlsStrongConsiderationPreds • keGenlsStrongSuggestionPreds keWeakSuggestionPreds • keGenlsStrongSuggestionInverse keRequirementPreds • keStrongConsideration keRequirementTernaryPreds • keStrongSuggestionPreds keGenlsWeakSuggestionPreds • keStrongSuggestionInverse keWeakSuggestionInverse • keWeakSuggestion keGenlsWeakSuggestionInverse • keInducedStrongSuggestionPreds keSuggestionApplies • keInteractionRequirement keStrongConsiderationPreds • keInteractionStrongSuggestion keRequirement • keNeighborSuggestion kePlausibleConsideration • kePredArgStrongSuggestionInverse • kePredArgWeakSuggestionPreds • kePredArgWeakSuggestionInverse • kePredArgStrongSuggestionPreds relationExistsAll • keStrongConsiderationInverse relationAllExists 13

15. Mapping Assertions to a Less Expressive Ontology • Assertions that cannot be asserted in that ontology need not be ignored when generalized forms of such assertions can be generated. • Can generalize relations • Can generalize/specialize arguments • Useful meta-predicates for specializing arguments are #$transitiveViaArg and #$transitiveViaArgInverse. . 14

16. Inferred Mapping Ontology 1 sentence to map: (residesInRegion GeorgeWBush NorthwestWashington) Ontology 2 cannot express since does not have NorthwestWashington, but has DC: (synonymousExternalConcept (TerritoryFn CityOfWashingtonDC) Ontology2 "washingtonDCUSA") (synonymousExternalConcept residesInRegion Ontology2 "resides") (synonymousExternalConcept GeorgeWBush Ontology2 "georgeWalkerBush") . 15

17. Inferred Mapping (cont.) Cyc knows that #$residesInRegion is transitive via #$geographicalSubRegions: (transitiveInArgInverse residesInRegion 2 geographicalSubRegions) Cyc knows that Northwest DC is part of DC: (geographicalSubRegions (TerritoryFn WashingtonDC) NorthwestWashington) Cyc concludes something directly mappable: (residesInRegion GeorgeWBush (TerritoryFn WashingtonDC)) And translates: georgeWalkerBush[resides->> washingtonDCUSA] . 16

18. Summary • New classes, relations, and individuals are created to merge in a foreign ontology. • Unwanted terms are functionally linked. • Special forms are used for irregular mappings. • Tools suggest new knowledge to enter. • Imported assertions have own context. • On export, assertions are generalized (weakened) as necessary. 17

19. (and (isa ?QUESTION RequestingInformation) (topicOf ?QUESTION (SubcollectionOfWithRelationToTypeFn OntologyMerging informationTerminal CycTheCollection)) (startsRelativeToEndOf ?QUESTION (MinutesDuration 15) Now)) Questions? . 18

22. CycL Syntax • Lisp-format syntax • (relation ?ARG1 ... ?ARGN) • If relation is a predicate the value is true or false. • If relation is a function, the value is an instance of the function’s result class. • Constant syntax: #$Name(can be displayed w/out “#$”) • Names have initial letter and subsequent letters, numbers, ‘-’, and/or ‘_’ • Variable syntax: ?VARIABLE A1

23. CycL Syntax Conventions • Name is lower-case for predicates, otherwise starts with capital letter • Function name ends in "Fn" (and start with capital letter) • No Class/Individual syntactical distinction • Multi-word names have initial caps for all interior words • Names, incl. variable names, should imply semantics A2

24. CycL Terminology • #$Collection = Class, something that has instances • #$Individual • non-set/class (incl. relations, strings, numbers) • #$FirstOrderCollection (“concept”) • Class whose instances are only #$Individuals • #$isa = instance of • #$genls = subclass of (“is-a”) • #$genlPreds = subrelation (#$genlInverse ...) • #$Microtheory -- context for assertions • logical world in which formula is true • #$genlMt = all assertions lift to first context • Operators are built-in code-supported #$Predicates: • #$and #$or #$not #$implies #$arity #$thereExists • #$assertedSentence #$knownSentence #$arg1Isa • #$interArg[Isa/Genl/Reln/Format]N-M #$resultIsa A3

25. CycL Examples • Sentence: (#$isa #$Individual #$Collection) • Rule: (#$implies (#$and (#$isa ?INSTANCE ?CLASS) (#$genls ?CLASS ?SUPERCLASS)) (#$isa ?INSTANCE ?SUPERCLASS)) • Function: (#$comment (#$BodyPartFn #$DouglasFoxvog #$Nose) “Doug Foxvog’s nose”) • Argument Type Specification: (#$isa #$BodyPartFn #$UnaryFunction) (#$arg1Isa #$BodyPartFn #$Animal) (#$arg2Isa #$BodyPartFn #$UniqueAnatomicalPartType) (#$resultIsa #$BodyPartFn #$AnimalBodyPart) (#$resultIsaArg #$BodyPartFn 2) (#$BodyPartFn #$DouglasFoxvog (LeftFn #$Ear)) “Doug Foxvog’s left ear”) A4 451015161719