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Curs 3 : Analiza unei lucrări. O primă şedinţă de “avocaţi ai diavolului”. The Right Frontier Constraint Holds Unconditionally. Dan Cristea Lucrare care ar fi trebuit să fie prezentată la MAD-05, Berlin www.infoiasi.ro/~dcristea/publications.html. The Right Frontier Constraint.
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Curs 3: Analiza unei lucrări O primă şedinţă de “avocaţi ai diavolului”
The Right Frontier Constraint Holds Unconditionally Dan Cristea Lucrare care ar fi trebuit să fie prezentată la MAD-05, Berlin www.infoiasi.ro/~dcristea/publications.html
The Right Frontier Constraint • As an attachment constraint in an incremental development of a tree structure: • adjunction of an auxiliary tree on a node of a developing tree can be made only on a node belonging to the right frontier of the developing tree
The Right Frontier Constraint • As a referential constraint defining the regions of the discourse model • …
Anaphora and Discourse Constraints Nicholas Asher(University of Texas) “Over a decade of work on the relation between semantics and discourse has established the Right Frontier Constraint as a well confirmed linguistic constraint on discourse structure. After formulating the Right Frontier Constraint in a precise fashion and reviewing the evidence for if from a variety of sources, I want to consider some challenges to it. I will look at two sorts of troubling phenomena: the first is the way presuppositions and anaphoric definite descriptions can affect discourse structure and hence the Right Frontier Constraint, the second has to do with the way locality can sometimes seem to override the Right Frontier Constraint. I will then reformulate the Right Frontier Constraint so as to take account of the data.”
RFC can be violated!… From (Sassen&Kühnlein, 2005) a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it.
RFC as conditional • …v. CICling 2005
Principle of Sequentiality A left-to-right reading of the terminal frontier of a discourse tree associated to a text corresponds to the span of text analysed, in the same linear order. (Marcu, 2000), etc.
transformed tree auxiliary tree developing tree transformed tree developing tree Y elementary tree X Y X X substitution node foot node X Adjunction Substitution Operations inspired by TAG
The Right Frontier Property At any step of an incremental discourse parsing, if the DT does not contain substitution nodes, the SP is observed if and only if all operations are adjoinings of left-footed ATs onto nodes of the right frontier of the DT.
The Right Frontier Property auxiliary tree transformed tree developing tree Y Y X y 0 0 X 1 y 1 Adjunction of a left-footed AT on the RF of the DT
The Right Frontier Property auxiliary tree transformed tree developing tree Y Y X a1 a2 0 0 X 1 a1 a2 1 Adjunction of an AT which is not left-footed
The Right Frontier Property auxiliary tree transformed tree developing tree Y Y Y X a1 a2 2 0 2 0 X 1 a1 a2 1 Adjunction of an AT on a node which does not belong to the RF of the DT
RFC can be violated!… a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it. A: to this you have to find a solution immediately.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it. A: to this you have to find a solution immediately.
RFC can be violated! a. B: I’ve recently felt confused when seeing Maria talking with Michael. b. B: The reason I’m asking your advise is that I’ll have my degree in June and right now I’m not in my best shape. a. A: oh yea, then, what we have here is a nice case of jealousy. a. B: would you say that I’m indeed only jealous? c. B: do you have another consultation hour scheduled soon? b. A: Try to be with yourself after all you’re heading for your final degree! b. B: mhm, well, but concentrating on my studies often doesn’t work c. A: yes, always on Monday. a. A: only jealous that would already suffice as problem, but I think there is more to it. A: to this you have to find a solution immediately.
a1 a2 b1 b2 a3 a4 b3 c1 c2 r1 r2 r3 r4 r5 r6
Merge a1. A: how was your trip to Braşov? b1. A: oh, did I tell you? I have seen yesterday evening Michael in the disco. b2. A: did you meet him anymore since you two split? a2. B. Fantastic! lot’s of nice guys and lot of fun.
Merge a1. A: how was your trip to Braşov? b1. A: oh, did I tell you? I have seen yesterday evening Michael in the disco. b2. A: did you meet him anymore since you two split? a2. B. Fantastic! lot’s of nice guys and lot of fun. B: wow, but, you know, he was too in that trip!
a1 a1 a2 b1 b1 b2 a2 b2 Merge of two DTs r r1 r1 r2 r2 ab r ab
r r1 r1 Fantastic! lot’s of nice guys and lot of fun. how was your trip to Braşov? Fantastic! lot’s of nice guys and lot of fun. how was your trip to Braşov? r2 r2 oh, did I tell you? I have seen yesterday evening Michael in the disco. did you meet him anymore since you two separated? r did you meet him anymore since you two separated? wow, but, you know, he was too in that trip! oh, did I tell you? I have seen yesterday evening Michael in the disco. Merge of two DTs wow, but, you know, he was too in that trip!
Splitting ab1. A: so, you didn’t know that I finished with Michael?! ab2 A: it happened last month after I came back from Mexico. a3. B: oh, I’m sorry, are you still mourning after him or you have already someone else? a4. A: negative! I’m ok but need a period of loneliness. a5. B: you cannot resist long like this. I know you… b3. B: so, have you seen the pyramids there?
Splitting a DT r2 r3 r1 B: oh, I’m sorry, are you still mourning after him or you have already someone else? r4 A: it happened last month after I came back from Mexico. A: so, you didn’t know that I finished with Michael?! B: you cannot resist long like this. I know you… A: negative! I’m ok and need a period of loneliness. r1 A: it happened last month after I came back from Mexico. A: so, you didn’t know that I finished with Michael?! r1 r5 A: so, you didn’t know that I finished with Michael?! B: so, have you seen the pyramids there? A: it happened last month after I came back from Mexico.
Splitting a DT r2 r3 r1 B: oh, I’m sorry, are you still mourning after him or you have already someone else? r4 A: so, you didn’t know that I finished with Michael?! B: you cannot resist long like this. I know you… A: negative! I’m ok and need a period of loneliness. r5 B: so, have you seen the pyramids there? A: it happened last month after I came back from Mexico.
A problem… r2 r3 r1 B: oh, I’m sorry, are you still mourning after him or you have already someone else? r4 A: it happened last month after I came back from Mexico. A: so, you didn’t know that I finished with Michael?! B: you cannot resist long like this. I know you… A: negative! I’m ok and need a period of loneliness. B: so, have you seen the pyramids there? How could Mexico be evoked by theresince it belongs to a span which is closed ?
Referential means • Weak • pronouns (including zero) • demonstratives • Strong • proper nouns • noun phrases (bridges or coreferential) Nothing is really forgotten…
Conclusions • RFC holds! • not only because a whole class of dedicated scholars have found examples to support it • because there is a simple theoretical proof for it • Discourse should be represented by graphs, not trees • Not only chats, but long discourses too • Graphs can represent multi-threads: • splitting a thread onto two • merging two distinct threads onto one • interruptions and flashbacks • there are more developing Right Frontiers on a discourse graph • hopping from a RF to another needs strong referential means