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Handling Unlike Coordinated Phrases in TAG by Mixing Syntactic Category and Grammatical Function Carlos A. Prolo Faculdade de Informática – PUCRS CELSUL, Oct. 2008
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VP VP * Adv NP N S V VP Lexicalized Tree Adjoining Grammar (LTAG)
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VP VP * Adv NP N S V VP S NPVP Adv V NP N N LTAG: combining trees 4 Tree Substitution Tree Adjunction
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VP VP * Adv NP N S V VP 4 NP DT NP * Lexicalized Tree Adjoining Grammar (LTAG)
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VP VP * Adv NP N S V VP 4 NP N [John] [apple] [quickly] [ate] NP DT NP * [the] Lexicalized Tree Adjoining Grammar (LTAG)
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VP VP * Adv NP N S V VP S NPVP Adv V NP N N LTAG: combining trees 4 Tree Substitution Tree Adjunction NP N [John] [apple] [quickly] [ate] NP DT NP * [the] DT NP [the] [apple] [John] [ate] [quickly]
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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S NP V VP S NP V VP S NP S NP V VP S NP NP NP * Domain of locality: head and arguments in the same tree 5 [eat] Declarative Wh- object movement Rel. Clause, subject relativ.
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S NP V PP VP Lexicalization, Domain of locality 4 P NP [account] [for]
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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VP VP * Adv S NP V VP S NPVP Adv V NP Factoring of recursion 4
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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VP VP * Adv NP N S NP S V NP O VP S NPVP Adv V NP N N Dependencies: NP N [John] [apple] [quickly] [ate] NP DT NP * [the] DT NP [the] [apple] [John] [ate] [quickly] ate John apple quickly NP S NP O VP Derivation tree Derived tree [the] NP
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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FB-LTAGs S NP V VP S NP V VP S NP [eat] Declarative Wh- object movement [wh=+] [ref= ] [wh=-] PRO [fin=-] [fin= ]
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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Wide-coverage grammars Handcrafted XTAG grammar (English) French grammar (Paris 7) Automatically extracted from corpora Chen & Vijay-Shanker Chiang Xia
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S NP 0 V NP 1 VP S NP V NP 1 VP S NP 1 V VP S NP 0 S NP V VP S NP 1 S NP V NP 1 VP S NP 0 NP NP * XTAG grammar: Verb Trees 5
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S NP 0 V NP 1 VP S NP V NP 1 VP S NP 1 V VP S NP 0 S NP V VP S NP 1 S NP V NP 1 VP S NP 0 NP NP * XTAG grammar: Verb FamilyTransitive 6
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Architecture of the XTAG English grammar A set of verb tree families. Each family: Roughly corresponds to a subcategorization frame Contain a set of elementary trees corresponding to each of the possible final realizations of the frame, e.g.: declarative, wh-subject, passive, etc. A set of individual trees for the other syntactic categories
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Trees for the verb “put” Declarative tree for “put”: “He put the book on the table”
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Trees for the verb “put”: the “put” family Declarative tree for “put”: “He put the book on the table” Subject extracted tree for “put”: “Who put the book on the table”
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More trees from the “put” family Passive tree for “put”: “The book was put on the table by him” Passive with subject extraction for “put”: “What was put on the table by him”
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TreeAdjoining Grammars the SUBSTITUTION operation A A A A + = intial tree
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TreeAdjoining Grammars the ADJUNCTION operation A A A*A* A A A + = auxiliary tree
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VP VP * Adv NP N S V VP 4 NP DT NP * Lexicalized Tree Adjoining Grammar (LTAG)
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VP VP * Adv NP N S V VP 4 NP N [John] [apple] [quickly] [ate] NP DT NP * [the] Lexicalized Tree Adjoining Grammar (LTAG)
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Features of LTAGs 1.Lexicalization 2.Domain of locality 3.Factoring of recursion 4.Rich descriptions 5.Dependencies 6.A grammar formalism, not a linguistic theory 7.Can have “feature” equations (FB-LTAGs) 8.Wide coverage grammars 9.Parsers
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VP VP * Adv NP N S V VP S NPVP Adv V NP N N LTAG: combining trees 4 Tree Substitution Tree Adjunction NP N [John] [apple] [quickly] [ate] NP DT NP * [the] DT NP [the] [apple] [John] [ate] [quickly]
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VP VP * Adv NP N S NP S V NP O VP S NPVP Adv V NP N N Dependencies: NP N [John] [apple] [quickly] [ate] NP DT NP * [the] DT NP [the] [apple] [John] [ate] [quickly] ate John apple quickly NP S NP O VP Derivation tree Derived tree [the] NP
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VP VP * Adv NP N S NP S V NP O VP S NPVP Adv V NP N N Dependencies 4 ate[green] John[red] apples[red] quickly[yellow] NP S NP O VP Derivation tree Derived tree
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FB-LTAGs S NP V VP S NP V VP S NP [eat] Declarative Wh- object movement [wh=+] [ref= ] [wh=-] PRO [fin=-] [fin= ]
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Wide-coverage grammars Handcrafted XTAG grammar (English) French grammar (Paris 7) Automatically extracted from corpora Chen & Vijay-Shanker Chiang Xia
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Parsers “All-parses” parsers Schabes/Paroubek Sarkar Boullier High accuracy “best-parse” parsers Chiang Sarkar Very fast “deterministic” “best-parse” parsers Prolo: EMNLP02, IWPT00 (LR parser, decisions based on statistics, deterministic with limited amount of backtracking)
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VP VP * Adv NP N S NP 0 V NP 1 VP XTAG grammar: Examples of elementary trees 3
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VP VP * Adv NP N S NP 0 V NP 1 VP XTAG grammar: combining trees
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VP VP * Adv NP N S NP 0 V NP 1 VP XTAG grammar: combining trees
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VP VP * Adv NP N S NP 0 V NP 1 VP XTAG grammar: combining trees
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VP VP * Adv NP N S NP 0 V NP 1 VP S NPVP Adv V NP N N XTAG grammar: combining trees 4
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S NP V VP S NP V VP S NP S NP V VP S NP NP NP * Domain of locality: head and arguments in the same tree 5 [eat] Declarative Wh- object movement Rel. Clause, subject relativ.
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S NP V PP VP Lexicalization, Domain of locality 4 P NP [account] [for]
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S NP 0 V NP 1 VP S NP V NP 1 VP S NP 1 V VP S NP 0 S NP V VP S NP 1 S NP V NP 1 VP S NP 0 NP NP * XTAG grammar: Verb Trees 5
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S NP 0 V NP 1 VP S NP V NP 1 VP S NP 1 V VP S NP 0 S NP V VP S NP 1 S NP V NP 1 VP S NP 0 NP NP * XTAG grammar: Verb FamilyTransitive 6
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Architecture of the XTAG English grammar A set of verb tree families. Each family: Roughly corresponds to a subcategorization frame Contain a set of elementary trees corresponding to each of the possible final realizations of the frame, e.g.: declarative, wh-subject, passive, etc. A set of individual trees for the other syntactic categories
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Trees for the verb “put” Declarative tree for “put”: “He put the book on the table”
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Trees for the verb “put”: the “put” family Declarative tree for “put”: “He put the book on the table” Subject extracted tree for “put”: “Who put the book on the table”
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More trees from the “put” family Passive tree for “put”: “The book was put on the table by him” Passive with subject extraction for “put”: “What was put on the table by him”
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Description of trees of the “put” family (excluding relative clauses) 7
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Overview of current coverage of the XTAG verb tree families 8
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Trees not generated (80) Idiosyncratic trees: 30 “-ed” adjectives, restricted to transitives (“an eaten apple”) Trees with punctuation in the sentential compl. Fams. Determiner Gerund trees (“the finding of the treasure”) Not yet handled yet: 48 Passivization of “2 nd object” in idioms: (“The warning was taken heed of”) Occurrence of “by-phrase” in passives in non-final position (“I was told by Mary that...”) Note: “... given by Lee to Sandy” (Gazdar et al. 85) Other: 2 21
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Unlike Coordinated Phrases (UCP) (NP (UCP (NN construction) (CC and) (JJ commercial)) (NNS loans)) (VP (VB be) (UCP-PRD (NP (CD 35)) (CC or) (ADJP (JJR older)))) (VP (VB take) (NP (NN effect)) (UCP-TMP (ADVP 96 days later) (,,) (CC or) (PP in early February)))
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Unlike Coordinated Phrases (UCP) (NP (UCP (NN construction) (CC and) (JJ commercial)) (NNS loans)) (VP (VB be) (UCP-PRD (NP (CD 35)) (CC or) (ADJP (JJR older)))) (VP (VB take) (NP (NN effect)) (UCP-TMP (ADVP 96 days later) (,,) (CC or) (PP in early February))) NP NP * UCP JJ NNCC S NP VB UCP VP [be]
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Unlike Coordinated Phrases (UCP) We give the UCP the status of an independent non-terminal as if it had some intrinsic categorial significance Multiple conjunts: it is enough for one of them to be of a distinct category to turn the entire constituent into a UCP
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Unlike Coordinated Phrases (UCP): as the head of a constituent (S (NP-SBJ-1 The Series 1989 B bonds) (VP (VBP are) (VP (VBN rated) (S *-1 double-A)))) (S (NP-SBJ-1 The Series 1989 B bonds) (VP (VBP are) (UCP-PRD (ADJP-PRD (JJ uninsured)) (CC and) (VP (VBN rated) (S *-1 double-A)))))
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Mixing Syntactic Categoryand Grammatical Function Coordination works over the Grammatical Functions and not the Syntactic Categories She flew yesterday. She flew on July 4 th (Adverbial adjuncts) Hence: She flew yesterday and on July 4th. They sell electronic devices. They sell computer devices (adnominal adjuncts) Hence: They sell electronic and computer devices. I know the answer. I know that you don´t know it. (Internal arguments of “know”) Hence: I know the answer and that you don´t know it.
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Mixing Syntactic Categoryand Grammatical Function: Elementary trees for intransitive main clause and for NP subject Main Subj S Pred VP V N NP Substitution nodes (for arguments) are Grammatical Functions Corresponding Initial Trees are rooted by Grammatical Function nodes
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Mixing Syntactic Categoryand Grammatical Function: Elementary trees for left adnominal adjuncts NP AdnAdjLeft NP * NP N AdnAdjLeft NP * NP A Adjunction takes place at Syntactic Category nodes for modifiers, adjuncts … Corresponding auxiliary trees have Syntactic Category root and foot.
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Mixing Syntactic Categoryand Grammatical Function: Elementary trees for coordination of left adnominal adjuncts AdnAdjLeft NP AdnAdjLeft * CC AdnAdjLeft ADJP AdnAdjLeft * CC Adjunction takes place at Grammatical Function nodes for coordination and... what else???? Corresponding auxiliary trees have Grammatical Function root and foot.
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Conclusion Mixing Syntactic Category and Grammatical Function in the tagset of a generative grammar allows for handling linguistic phenomena which are syntactic in nature but rely on grammatical functions instead of syntactic categories Clearly coordination is one such phenomenon We would like to know other such cases We sketch a proposal of how to work out the idea in the Tree Adjoining Grammar formalism
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S NP V VP S NP V VP S NP S NP V VP S NP NP NP * Domain of locality: head and arguments in the same tree 5 [eat] Declarative Wh- object movement Rel. Clause, subject relativ.
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