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  1. Working with Discourse Representation TheoryPatrick Blackburn & Johan BosLecture 4Pronouns and Presupposition

  2. Today • Pronouns • Anaphoric pronouns • Binding constraints • Presupposition • Triggers • Problems • Van der Sandt • Implementation

  3. PRONOUNS

  4. Pronouns • We will concentrate on 3rd person singular personal pronouns in English: • he/him/himself • she/her/herself • it/itself

  5. Anaphoric Pronouns • We will focus on anaphoric pronouns • Anaphoric pronouns find their antecedent in the preceding text • Anaphora -- backwards Vincent looked at Mia. She dances.

  6. Anaphoric Pronouns • We will focus on anaphoric pronouns • Anaphoric pronouns find their antecedent in the preceeding text • Anaphora -- backwards Vincent looked at Mia. She dances. • She is the anaphor

  7. Anaphoric Pronouns • We will focus on anaphoric pronouns • Anaphoric pronouns find their antecedent in the preceeding text • Anaphora -- backwards Vincent looked at Mia. She dances. • Mia is the antecedent

  8. Anaphoric Pronouns • We will focus on anaphoric pronouns • Anaphoric pronouns find their antecedent in the preceeding text • Anaphora -- backwards Vincent looked at Mia. She dances. • How far backwards?

  9. Cataphoric Pronouns • We will not deal with cataphora • Cataphoric pronouns find their antecedent in the text following the pronoun • Example:After he lost the match, Butch left town.

  10. Cataphoric Pronouns • We will not deal with cataphora • Cataphoric pronouns find their antecedent in the text following the pronoun • Example:After he lost the match, Butch left town.

  11. Deictic Pronouns • Pronouns referring to objects in the situation, rather than linguistic objects • Examples:I, you, we, here, there, etc.

  12. Pleonastic use of pronouns • Example:It’s about nine o’clock in the morning.

  13. Grammatical agreement • In English, pronouns come with a gender and number feature • Only refer to antecedents carrying the same feature values: he (singular, male): men/boys, male animals she (singular, female): women/girls, female animals, things regarded as female, e.g. vehicles or ships it (singular, neuter): things, animals, children

  14. Pronouns and Ambiguity • Butch threw a TV at the window.It broke. • Butch threw a vase at the wall.It broke.

  15. Pronouns and Ambiguity • Butch threw a TV at the window.It broke. • Butch threw a vase at the wall.It broke.

  16. Pronouns and Ambiguity • Butch threw a TV at the window.It broke. • Butch threw a vase at the wall.It broke.

  17. Pronouns and Ambiguity • Butch threw a TV at the window.It broke. • Butch threw a vase at the wall.It broke.

  18. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and drinks it.

  19. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and drinks it.

  20. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and drinks it.

  21. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and drinks it.

  22. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and shuts it.

  23. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and shuts it.

  24. Pronouns and Ambiguity • Usually many candidate antecedents available • Example:Butch walks into his modest kitchen. He opens the refrigerator. He takes out a milk and shuts it.

  25. Reflexive Pronouns • Examples: • Vincent goes to the toilet, and Jules enjoys himself. • Vincent enters the restaurant, and Jules watches him.

  26. Reflexive Pronouns • Examples: • Vincent goes to the toilet, and Jules enjoys himself. • Vincent enters the restaurant, and Jules watches him.

  27. Reflexive Pronouns • Examples: • Vincent goes to the toilet, and Jules enjoys himself. • Vincent enters the restaurant, and Jules watches him.

  28. Binding rules • Behaviour of pronouns:Butch likes himself.Butch likes him.Butch likes his chopper.

  29. DRT and pronouns [1/3] • Vincent did not dance with a woman.She … 

  30. DRT and pronouns [2/3] • Vincent did with every woman. She … 

  31. DRT and pronouns [3/3] • Vincent did with no woman. She … 

  32. Summing up • We have looked at anaphoric pronouns • It is unlikely that we can solve all the problems related to resolving pronouns • However, we can deal with some important aspects • Semantic constrains [gender] • Binding constrains [reflexivity] • DRT constrains pronoun resolution, but only partially

  33. PRESUPPOSITION

  34. Presupposition • Presupposition vs. Entailment • Look at some examples of presupposition • Look at the typical problems associated with presuppositions • Concentrate on a DRT based approach due to Rob van der Sandt

  35. What is presupposition? • It is hard to pin down precisely what presuppositions are or how they behave • Presuppositions are a bit like entailment but not quite…

  36. Entailment • Consider:Vincent has a car. A car is a vehicle. • This entails: Vincent has a vehicle.

  37. Entailment • Consider:Vincent has a red car. • This entails: Vincent has a car.

  38. Entailment and negation • Entailments are typically not preserved under negation.

  39. Entailment • Consider:Vincent has no car. A car is a vehicle. • This does not entail: Vincent has a vehicle.

  40. Entailment • Consider:Vincent does not have a red car. • This does not entail: Vincent has a car.

  41. Presupposition • Consider:Vincent cleaned his car. • This entails:Vincent has a car.

  42. Presupposition • Consider:Vincent did not clean his car. • This entails:Vincent has a car.

  43. Entailment or presupposition • We call implications preserved under negation presuppositions • We call implications not preserved under negation entailments

  44. Presupposition triggers • In English, presuppositions are usually triggered by lexical items • There are several tricks to find out whether a lexical item is a presupposition trigger or not • These tests are: • The negation test • The conditional test • The question test

  45. Presupposition trigger test • Consider the sentence:Alex is a bachelor. • This sentence implies that Alex is male. • But are we dealing with a presupposition or entailment?

  46. Presupposition test • Alex is a bachelor.Does this presuppose: Alex is male?

  47. Presupposition test • Alex is a bachelor.Does this presuppose: Alex is male? • Negation: Alex is not a bachelor.Implies: Alex is male? YES

  48. Presupposition test • Alex is a bachelor.Does this presuppose: Alex is male? • Negation: Alex is not a bachelor.Implies: Alex is male? YES • Conditional: If Alex is a bachelor, then ...Implies: Alex is male? YES

  49. Presupposition test • Alex is a bachelor.Does this presuppose: Alex is male? • Negation: Alex is not a bachelor.Implies: Alex is male? YES • Conditional: If Alex is a bachelor, then ...Implies: Alex is male? YES • Question: Is Alex is a bachelor?Implies: Alex is male? YES

  50. Presupposition test • Alex is a bachelor.Does this presuppose: Alex is male? • Negation: Alex is not a bachelor.Implies: Alex is male? YES • Conditional: If Alex is a bachelor, then ...Implies: Alex is male? YES • Question: Is Alex is a bachelor?Implies: Alex is male? YES • Conclusion: being a bachelor presupposes being male.