CSCI 587 - Lecture 16 Parsing Auxiliaries

• Review Parsing with Features: a fish
  1. Word = a
  2. C = (ART ROOT A AGR 3s)
  3. Matches the Rule (NP AGR ?a) -> . (ART AGR ?a) (N AGR ?a)
  4. But in matching we assign variable ?a = 3s
  5. To obtain the Arc (NP AGR 3s) -> (ART AGR 3s) . (N AGR 3s)
  6. after seeing fish that extends this arc further we "reduce" and add the constituent (NP AGR 3s) to the chart
• Prolog Parse Trees as functors (nlp4)
• Features in Prolog
  • list of features
  • functor
• Auxiliary Verbs: have, be, do, can, will, ...

          We can win the game.
          We will have won the game by halftime.
          I was watching Melvin.
          I should have been watching the ball.
          We will do better next year.
          I am not going to put up with this.
          We could not have seen this one coming.
  

• Distinguishing Aux and main-verbs
  • Aux can be inserted before adverbial not
  • Aux can precede the subject NP in Yes/No questions

            Can we win the game ?
            Will we have won the game by halftime?
            Were you watching Melvin?
    

  • Main-verbs may appear as the sole verb; require do for yes/no

          We lost the game.
          Did we lose the game?
  

• Primary Auxiliaries: forms of be and have
• Modal Auxiliaries
  • do/did
  • can/could
  • may/might
  • shall/should
  • will/would
  • must
  • need
• Auxiliary phrases: ought to, used to, be going to
• Have: Aux of main-verb
  • as an aux have requires past-participle
  • as main-verb have requires NP complement
• Extending the grammar to handle auxiliaries
  VP -> (AUX COMPFORM ?f)(VP VFORM ?f)
• COMPFORM feature restrictions (fig 5.1)
• Order of auxiliaries

  Modal + have + be(progressive) + be (passive)
  The game might have been being played without Fogler.

• modals can never follow have or be, since they have no past-participle
• MAIN feature: binary + for main-verbs, - for auxs
• PASS(passive feature): VP -> AUX[be] VP[pastptr, main]
• subject-aux inversion
• CUT in prolog

Readings

Sections 5.1-5.2