LTAG Semantics for Questions: LTAG Semantics for Questions Aleksandar Savkov


Contents : Contents Introduction Hamblin’s idea Karttunen’s upgrade Goals of the paper Scope properties of wh-phrases Quantificational NPs Wh-phrases as quontifiers Multiple wh-questions Long-distance wh-dependencies Comparison to other approaches Embedded interrogatives Ambiguity in multiple wh-questions References


Introduction: Introduction Hamblin’s semantics for questions Every question denotes a set of propositions expressed by its possible answers Who came? {‘Bill came.’, ‘John came.’, ‘Dan came.’…} Is it raining? {‘It’s raining.’, ‘It’s not raining.’}


Introduction: Introduction Karttunen’s upgrade Every question denotes a set of propositions expressing only true answers


Introduction: Introduction Goals of the paper (Romerom Kallmeyer, Babko-Malaya 2004) capture scope properties of quantificational elements within the question achieve the correct semantics for interrogatives embedded under e.g. know


Introduction: Introduction Example of different scopes for wh- and non-wh-quantifiers:


Introduction: Introduction Example for multiple wh- phrases:


Introduction: Introduction Example for correct semantics of interrogatives:


Scope properties of wh-phrases: Scope properties of wh-phrases Quantificational NPs Wh-phrases as quontifiers Multiple wh-questions Long-distance wh-dependencies Comparison to other approaches


Quantificational NPs: Quantificational NPs We assume quantifiers as everybody have a multi-component set containing an auxiliary tree (contributes to the scope part) and an initial tree (contributes the predicate argument)


Slide11: every(x,person(x,s0),laugh(x,s0))


Slide12: disambiguation: 3 -> l3, 4 -> l1 every(x,person(x,s0),laugh(x,s0))


Wh-phrases as quantifiers: Wh-phrases as quantifiers Repeating the Karttunen style


Wh-phrases as quontifiers: Wh-phrases as quontifiers 5 -> l4, 9 -> l5, 10 -> l2, 7 -> l6, 14 -> l7, 15 -> l1 Q3:λp.p(s0) and some(x,person(x,s0), p=λs.every(y,person(y,s/s0), like(x,y,s)))


Multiple wh-questions: Multiple wh-questions To treat in situ wh-quantifiers correctly we need the minimal scope of any NP substitution node To achieve that we need both minimal scopes for wh- and non-wh-quantifiers We will use the feature WH for the wh-quantifier and P for the non-wh


Long-distance wh-dependencies: Long-distance wh-dependencies In long distance wh-dependencies, one must make sure that the wh-quantifier scopes over all verbs in the sentence in order to provide argument for the most embedded one.


Long-distance wh-dependencies: Long-distance wh-dependencies


Comparison to other approaches: Comparison to other approaches Karttunen style semantics Ginzburg and Sag, 2000 Our approach


Karttunen style semantics: Karttunen style semantics Draws distinction between wh-scope and non-wh-scope Uses different semantic types for all the relevant categories Wh-quantifiers combine with functions of type from situations to sets of propositions Thus all wh-quantifiers must scope over all non-wh-quantifiers


Ginzburg and Sag: Ginzburg and Sag Ontological distinction between state-of-affairs (SOA) and propositions One builds propositions, questions, outcomes and facts from SOAs Non-wh-quantifiers have SOA nuclear scope and wh-quantifiers have proposition and thus the second one is wider


Our approach: Our approach We use a ‘flat’ semantic framework in the style of MRS (Copestake et al.1999) Semantic contribution of the elementary and auxiliary trees is a set of formulas No type distinction can be made to which of the scope properties of wh- and non-wh-quantifiers could relate No distinction between SOA and propositions MAXS, WH and P features and feature unification are used to define appropriate scope windows.


Embedded interrogatives: Embedded interrogatives Unless bound by an operator situation arguments are replaced by the utterance situation In embedded interrogatives the issue is how to bind the situation variable


Embedded interrogatives: Embedded interrogatives


Embedded interrogatives: Embedded interrogatives


Ambiguity in multiple wh-questions: Ambiguity in multiple wh-questions Some multiple wh-questions are ambiguous Example: Who remembers where Mary keeps which book? This could be read in two different ways: Bill remembers where Mary keeps which book. Joe remembers where Mary keeps Aspects and Max remembers where Mary keeps Syntactic Structures


References : References LTAG Semantics for Questions (Romero, Kallmeyer, Babko-Malaya, 2004) Syntax and semantics for questions (Karttunen)