Exercise 4.1

Find out how copula verbs are handled in the lexicon and grammar, and how our implementation generates the semantic representations for sentences like ``Mary is a therapist'' and ``Mary is not John''. You may either hand in your solution in (hand-)written form or send us a an E-mail. In the latter case, you can use the Prolog notation for -terms. E.g. for ``John walks'', the solution might look like this:

John  ~> lambda(A,A@john)
walks ~> lambda(B,walk@B)
 
John walks ~> lambda(A,A@john)@lambda(B,walk(B))
 
           ...  
 
           <=> walk(john).  

Exercise 4.2

Add a treatment of ditransitive verbs such as ``offer'' to the implementation discussed in this chapter. Use the following formalization as a starting point:

Hint: Move along the lines of transitive verbs. First specify the lexicon/4-fact and the lexical and phrasal DCG rules. Then specify the semantic macro and finally design an appropriate combine rule. Don't forget the brackets in your complex applications, e.g. ((A@B)@C)!

Test your solution with sentences like ``Mary offers John a siamese cat.''

Exercise 4.3

Find a suitable -expression for the determiner ``no'' (or use what you've thought out in Exercise 3.4) and add it to our implementation. Test your solution with sentences like ``No man walks.''

[Hint: remember the special treatment of determiners!]

Exercise 4.4

Extend our implementation such that it covers negated sentences like ``It is not the case that Mary walks.''

Hint: Find out how if-then-sentences are treated.

Exercise 4.5

This is an important exercise!

Test the coverage of our system. Try to find some sentences where the semantic representations returned by our implementation are not satisfactory. Are the problems due to our implementation, or due to the mechanism of -based semantic construction itself?

Exercise 4.6

[Mid-term project]

Localize the system we've implemented. That is, take it to a language of your choice by adapting the lexicon and grammar accordingly. The range of constructions and phenomena covered should be the same or comparable to what is covered by the English version we've discussed. If you want to cover different semantic phenomena, you'll probably have to extend the semantic macros, too.

Your solution should contain a sort of report, documenting the changes you make, as well as the difficulties you encounter. Do you think that the difficulties are particular to the language you've chosen? Does the modular character of the system support you in your work?