1. cse@buffalo S.C. Shapiro Knowledge Representation for Natural Language Competence Stuart C. Shapiro Department of Computer Science and Engineering and Center for Cognitive Science State University of New York at Buffalo shapiro@cse.buffalo.edu

2. cse@buffalo S.C. Shapiro Motivation Deep understanding of NL texts requires a Knowledge Representation & Reasoning formalism/system. A variety of logic. But not the logic for metamathematics.

3. cse@buffalo S.C. Shapiro Preview I will discuss several issues in KRR for NL Competence, Illustrated by interactions with a computational agent. Agent: Cassie. KRR system: SNePS. Interactions are transcribed from consecutive interactions in a single session.

4. cse@buffalo S.C. Shapiro Interaction with Cassie English (Statement, Question, Command) (Current) Set of Beliefs [SNePS] (Updated) Set of Beliefs [SNePS] Actions [SNeRE] (New Belief) [SNePS] English sentence expressing new belief answering question reporting actions Answer [SNIP] GATN Parser GATN Generator Reasoning Clarification Dialogue Looking in World Reasoning

5. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

6. cse@buffalo S.C. Shapiro Intensional Entities 1 Rather than represent “objects in the world,” represent mental entities. Includes Imaginary and Fictional Entities. Multiple mental entities may correspond to one world object. –Intensional entities may be co-extensional. –But must be kept separate.

7. cse@buffalo S.C. Shapiro Intensional Entities 2 : The morning star is the evening star. I understand that the morning star is the evening star. : The evening star is Venus. I understand that Venus is the evening star. : Clark Kent is Superman. I understand that Superman is Clark Kent.

8. cse@buffalo S.C. Shapiro Intensional Entities 3 : Lois Lane saw Clark Kent. I understand that Lois Lane saw Clark Kent. : Did Lois Lane see Superman? I don't know. : Did Lois Lane see Clark Kent? Yes, Lois Lane saw Clark Kent. Note Open World Assumption.

9. cse@buffalo S.C. Shapiro Intensional Entities 4 : Superman went to the morning star. I understand that Superman went to Venus. : Did Clark Kent go to Venus? Yes, Superman went to Venus.

10. cse@buffalo S.C. Shapiro Intensional Entities 5 : Buck Rogers went to the evening star. I understand that Buck Rogers went to Venus. : Who went to Venus? Buck Rogers went to Venus and Superman went to Venus.

11. cse@buffalo S.C. Shapiro Intensional Entities 6 The morning star The evening star Venus Superman Clark Kent Buck Rogers Lois Lane Go to See

12. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

13. cse@buffalo S.C. Shapiro Complex Categories 1 Noun Phrases: {N | Adj}* N Understanding of the modification must be left to reasoning. Example: orange juice seat Representation must be left vague.

14. cse@buffalo S.C. Shapiro : Kevin went to the orange juice seat. I understand that Kevin went to the orange juice seat. : Did Kevin go to a seat? Yes, Kevin went to the orange juice seat. Complex Categories 2

15. cse@buffalo S.C. Shapiro : Pat is an excellent teacher. I understand that Pat is an excellent teacher. : Is Pat a teacher? Yes, Pat is a teacher. : Lucy is a former teacher. I understand that Lucy is a former teacher. Complex Categories 3

16. cse@buffalo S.C. Shapiro : `former' is a negative adjective. I understand that `former' is a negative adjective. : Is Lucy a teacher? No, Lucy is not a teacher. Complex Categories 4

17. cse@buffalo S.C. Shapiro PseudoRepresentation of Complex Categories Isa(B30, CompCat(orange, CompCat(juice, seat))) Isa(Pat, CompCat(excellent, teacher)) Isa(Lucy, CompCat(former, teacher))

18. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

19. cse@buffalo S.C. Shapiro Possession I.1 “One man’s meat is another man’s poison.”

20. cse@buffalo S.C. Shapiro : Richard's meat is Henry's poison. I understand that Henry's poison is Richard's meat. : Edward ate Richard's meat. I understand that Edward ate Richard's meat. : Did Edward eat Henry's poison? Yes, Edward ate Henry's poison. Possession I.2

21. cse@buffalo S.C. Shapiro : Did Edward eat Henry’s meat? I don’t know. : Did Edward eat Richard's poison? I don’t know. Possession I.3 Moral: Possession is a three-place relation.

22. cse@buffalo S.C. Shapiro PseudoRepresentation of Possession Has(Richard, meat, B35) Has(Henry, poison, B37) Equiv(B35, B37)

23. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

24. cse@buffalo S.C. Shapiro Propositions about Propositions 1 Propositions are “first-class” mental entities. They can be discussed, just like other mental entities. And must be represented like other mental entities.

25. cse@buffalo S.C. Shapiro : That Bill is sweet is Mary's favorite proposition. I understand that Mary's favorite proposition is that Bill is sweet. : Mike believes Mary's favorite proposition. I understand that Mike believes that Bill is sweet. Propositions about Propositions 2

26. cse@buffalo S.C. Shapiro : That Mary's favorite proposition is that Bill is sweet is cute. I understand that that Mary's favorite proposition is that Bill is sweet is cute. Propositions about Propositions 3

27. cse@buffalo S.C. Shapiro Representing Propositions Representation of Proposition –Not by a Logical Sentence –But by a Functional Term –Denoting a Proposition.

28. cse@buffalo S.C. Shapiro PseudoRepresentation of Propositions about Propositions Has(Mary, CompCat(favorite, proposition), HasProp(Bill, sweet)) Believes(Mike, HasProp(Bill, sweet)) HasProp(Has(Mary, CompCat(favorite, proposition), HasProp(Bill, sweet)), cute)

29. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

30. cse@buffalo S.C. Shapiro Possession II.1 Examples from J. Lyons, Semantics I, 1977, p. 312, of inalienable possessive constructions: “John’s right arm” of alienable possessive constructions: “John’s book” Use vague representation with later reasoning.

31. cse@buffalo S.C. Shapiro : Caren held Stu's hand. I understand that Caren held Stu's hand. : Mary held Bill's book. I understand that Mary held Bill's book. Possession II.2

32. cse@buffalo S.C. Shapiro : What is an inalienable possession? I don't know. : What is an alienable possession? I don't know. Possession II.3

33. cse@buffalo S.C. Shapiro : Hands are body parts. I understand that hands are body parts. : Books are ownable objects. I understand that books are ownable objects. Possession II.4

34. cse@buffalo S.C. Shapiro : What is Stu's hand? Stu’s hand is the hand. : What is Bill's book? Bill’s book is the book. Possession II.5

35. cse@buffalo S.C. Shapiro : What is an inalienable possession? That Stu has a hand is the inalienable possession. : What is an alienable possession? That Bill has a book is the alienable possession. Possession II.6

36. cse@buffalo S.C. Shapiro PseudoRepresentation of Possession Has(Stu, hand, B47) Has(Bill, book, B49) Held(Caren, B47) Held(Mary, B49) Isa(Has(Stu, hand, B47), CompCat(inalienable, possession)) Isa(Has(Bill, book, B49), CompCat(alienable, possession))

37. cse@buffalo S.C. Shapiro Outline Introduction Intensional Entities Complex Categories Possession I Propositions about Propositions Possession II Summary

38. cse@buffalo S.C. Shapiro Summary Represent intensional (mental) entities. Open World Assumption Vague representation of complex categories. –Clarified by reasoning. Ability to discuss words. –NL is its own metalanguage. Possession as a three-place relation. Propositions as first-class entities. Vague representation of possession. –Clarified by reasoning. Supplying taxonomy via NL inputs.

39. cse@buffalo S.C. Shapiro SNePS Research Group Current Members Faculty: Stuart C. Shapiro, Director William J. Rapaport, Associate Director Carl Alphonce Jean-Pierre A. Koenig David R. Pierce Graduate Students: Marc BroklawskiBharat Bhushan Debra T. BurhansHaythem O. Ismail Frances L. JohnsonJohn F. Santore

40. cse@buffalo S.C. Shapiro For More Information URL: http://www.cse.buffalo.edu/~shapiro/http://www.cse.buffalo.edu/~shapiro/ Group: http://www.cse.buffalo.edu/sneps/http://www.cse.buffalo.edu/sneps/