CSCI 587 - Lecture 20 Compositional Semantics

• Discourse variables: "John" might map to several people
  (NAME variable name) denotes this binding of the name
  (PRONOUN variable proposition)
• Compositional Theory
  • Linguistics meaning
  • computational approaches
• Lambda calculus (Alonzo Church)- functions without names
• Examples of lambda expressions
• Lambda Reduction
• Why Lambda Calculus?
• Compositional representations of NP, VP, and PP
• (object-pred event-label "word")
  < The b1 Bucket >
• Representing VPs
  • John "ran".
  • John "kissed Mary".
  • John "read the book".
  • John "gave the book to Mary".
• Representing VPs as predicates
• Complex VPs: VP -> VP CONJ VP
  John kissed Mary and read the book.
• Prepositional Phrases (PP)
  • modifiers in NPs "the man in the green hat"
  • in the store
    "The man is in the store" vs "the man in the store"
    ( IN-LOC1 < THE m1 MAN1> < THE s1 STORE>)
    < THE m1 (MAN1 m1)(IN-LOC1 m1 < THE s1 STORE1>)>
• Prepositional Phrases (PP) as Predicates also
• NPs as terms (objects) in the logical representation
• Sentences as propositions
• Using these conventions for representing constituents we can compose them
• Augmenting the grammar with the SEM feature
• Adding to the lexicon (figure 9.2)
• Adding to the grammar rules (Grammar 9.3)
• (S SEM (?semvp ?semnp)) -> (NP SEM ?semnp)(VP SEM ?semvp)
• Parsing
• VAR feature - stores the discourse variable that corresponds to the constituent
• Morphological rules must be adapted also
• Review for Test2
  • NLP in Prolog
  • Parse Trees in Prolog
  • Bottom-Up Chart Parsing
  • Features
  • Parsing with Features
  • Parsing Auxiliaries
  • Parsing wh-Questions
  • Semantics
  • Semantics: Thematic Roles
  • Compositional Semantics

Readings

Sections 9.1-9.2

Reminder

Test 2 April 10