June 7th, 2008TAG+91 Binding Theory in LTAG Lucas Champollion University of Pennsylvania

June 7th, 2008 TAG+9 2 Overview Binding Theory (BT) and its local domains Previous work: Condition A This proposal: Conditions A, B, C Discussion

June 7th, 2008 TAG+9 3 Binding theory: A reminder Condition A: reflexives must be locally bound  John j thinks [ Bill b likes himself *j / b / *[other] ] Condition B: pronouns must be locally free  John j thinks [ Bill b likes him j / *b / [other] ] Condition C: full noun phrases must be free  *[ John j likes John j ]  *John j thinks [ Mary likes John j ]

June 7th, 2008 TAG+9 4 Binding theory in LTAG LTAG’s local domain = the verbal elementary tree and its arguments  (but not its adjuncts) Insight from previous work:  LTAG and BT have similar local domains This presentation’s central point:  Too many mismatches between local domains  We can’t reuse LTAG’s local domain for binding!

June 7th, 2008 TAG+9 5 Previous work reused LTAG’s local domain NP loves VNP VP S himself John NP VS* VP S thinks he Condition A

June 7th, 2008 TAG+9 6 Previous work reused LTAG’s local domain NP loves VNP VP S himself John NP VS* VP S thinks he Condition A

June 7th, 2008 TAG+9 7 Previous work reused LTAG’s local domain NP loves VNP VP S himself John NP VS* VP S thinks he Condition A

June 7th, 2008 TAG+9 8 Previous work reused LTAG’s local domain NP loves VNP VP S him John NP VS* VP S thinks he Condition B

June 7th, 2008 TAG+9 9 Ryant and Scheffler (2006) Only Condition A MCTAG set with a degenerate NP tree Tree-local MCTAG with flexible composition makes sure that antecedent and reflexive substitute into the same tree NP  loves VNP VP S himself NP i John NP NP* i {}

June 7th, 2008 TAG+9 10 Kallmeyer and Romero (2007) Only Condition A MCTAG set with a degenerate VP tree Tree-local MCTAG with flexible composition makes sure that antecedent and reflexive substitute into the same tree NP  loves VNP VP S himself NP i John NP VP* i {} (some features omitted)

June 7th, 2008 TAG+9 11 Kallmeyer and Romero’s claim “Tree-local MCTAG display exactly the extended domain of locality needed to account for the locality of anaphora binding in a natural way.” -- Kallmeyer and Romero (2007)

June 7th, 2008 TAG+9 12 A counterexample VP* opposite PNP PP VP himself John NP V VP S imagined Cannot be handled by Kallmeyer and Romero (2007)  except by flexible composition (which they try to avoid) Bill

June 7th, 2008 TAG+9 13 ECM: another mismatch of localities NP to love VNP VP S Bill John NP VS* VP S expects him Can be handled with an extra feature No lexical ambiguity needed (unlike R&S 2006)

June 7th, 2008 TAG+9 14 Mismatches within Binding Theory Bill NP himself NP  V VP S found John NP NP* ’s Det NP  N’ NP picture N P NP* PP NP of Bill NP him NP  V VP S found John NP NP* ’s Det NP  N’ NP picture N P NP* PP NP of Judgments tested experimentally (Keller and Asudeh ‘01; Runner ‘03) A A B B

June 7th, 2008 TAG+9 15 Mismatches within Binding Theory VP* near P PP VP himself John NP V VP S saw a snake NP VP* near P PP VP him John NP V VP S saw a snake NP A A B B

June 7th, 2008 TAG+9 16 How to encode the other conditions? Condition A roughly corresponds to tree- locality Condition B = “enforced non-locality”? Condition C = ???  Need to propagate an unbounded number of potential antecedents

June 7th, 2008 TAG+9 17 This account in a nutshell Every NP receives three items from its environment:  a list “A” of local potential antecedents  a list “B” of local potential antecedents  a list “C” of nonlocal potential antecedents Every NP supplies its own individual variable to its environment The rest of the grammar is responsible for providing the correct lists to the NP substitution slots

June 7th, 2008 TAG+9 18 Technical innovation: List-valued features

June 7th, 2008 TAG+9 19 Elementary tree for “himself” (Condition A, simplified) “A reflexive must be locally bound.”

June 7th, 2008 TAG+9 20 Elementary tree for “he” (Condition B) “A pronoun must be locally free.”

June 7th, 2008 TAG+9 21 Elementary tree for “John” (Condition C) “A full noun phrase must be free.”

June 7th, 2008 TAG+9 22 Sample derivation

June 7th, 2008 TAG+9 23 Sample derivation

June 7th, 2008 TAG+9 24 Sample derivation

June 7th, 2008 TAG+9 25 Sample derivation

June 7th, 2008 TAG+9 26 Condition C: the default case Before...

June 7th, 2008 TAG+9 27 Condition C: the default case...and after unification of top/bottom features

June 7th, 2008 TAG+9 28 Condition C across clauses Before putting the trees together...

June 7th, 2008 TAG+9 29 Condition C across clauses The higher tree passes its subject down, then...

June 7th, 2008 TAG+9 30 Condition C across clauses...unification at the root node propagates the empty list

June 7th, 2008 TAG+9 31 Improvements over previous accounts...

June 7th, 2008 TAG+9 32 Binding into adjuncts Just propagate everything!

June 7th, 2008 TAG+9 33 Mismatches between domains easily encoded Non-complementary binding conditions easily handled with separate A and B list features No ad hoc trees needed for picture NPs (unlike K&R ‘07)

June 7th, 2008 TAG+9 34 C-command violations easily encoded No need for separate lexical entry Just extrapose subject NP along with its feature structure (he) (Himself) e.g. extraposition: “Himself i, he i likes.”

June 7th, 2008 TAG+9 35 Improvements at a glance All conditions are implemented Higher empirical accuracy No lexical ambiguity No flexible composition (K&R 2007) No syntactically unmotivated degenerate trees (Kallmeyer and Romero, 2008) Better integration with anaphora resolution (Branco, 2002) No explicit representation of c-command

June 7th, 2008 TAG+9 36 Issues / Future work Unknown complexity of list-valued features  Just a decoration on the trees though -- they do not rule out any sentences Lack of predictive power  How do we constrain possible feature values?  Metagrammar? Does TAG offer any insights into BT at all?

June 7th, 2008 TAG+9 37 Thank you. Lucas Champollion University of Pennsylvania

June 7th, 2008 TAG+9 38 Previous accounts do not interface well with anaphora resolution modules Previous accounts: parser delivers a forest of indexed trees  John i introduced Bill k to himself i vs. John i introduced Bill k to himself k  Problem: Anaphora resolution modules are not prepared to compare entire trees (Branco, 2002) Our solution outputs a compact set of constraints  Following Branco (2002)

June 7th, 2008 TAG+9 39 The grammar of picture NPs NP* ’s Det NP  N’ NP Bill NP himself NP  V VP S found picture N P NP* PP NP of John NP

June 7th, 2008 TAG+9 40 Missing link problem NP* ’s Det NP  N’ NP Bill NP himself NP  V VP S found picture N P NP* PP NP of John NP