CS 4804 Homework #4

Date Assigned: February 19, 2003
Date Due: February 28, 2003, in class, before class starts
  1. (10 points) Solve problem 8.6 (k) of your textbook. Use only the predicates: Politician(x), Person(x), Fools(x,y,t). The first is true when "x" is a politician; the second is true when "x" is a person, and the third is true when "x" fools "y" at time "t".

  2. (10 points) Pickup a PROLOG manual and learn what the "cut" (!) is supposed to do. State the functionality of the cut in AI terminology. Give examples.

  3. (20 points) Give a scientific explanation using terminology that we have learned in CS 4804 for each of the following interactions with PROLOG:

    Interaction 1: 
    
is_own_successor(X) :- X = successor(X).
[accepted]
?- is_own_successor(X).
X = successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor(
    successor(successor(successor(successor(successor( .....
    Interaction 2: 
    
?- human(X).
X = bob.

?- not(not(human(X))).
X = _23.
  4. (30 points) You are given the following facts:

    1. The members of the Elm St. Bridge Club are Joe, Sally, Bill, and Ellen.
    2. Joe is married to Sally.
    3. Bill is Ellen's brother.
    4. The spouse of every married person in the club is also in the club.
    5. The last meeting of the club was at Joe's house.

    Our aim is to decide on the truth of the following two sentences from the above five facts:

    1. The last meeting of the club was at Sally's house.
    2. Ellen is not married.

    Construct resolution proofs to demonstrate the truth of each of the above two statements. You might need to add additional statements to the given database. For full credit, state which of the resolution strategies (input resolution, linear resolution, unit resolution, set-of-support resolution) is sufficient.

  5. (30 points) Exercise 9.19 of your textbook.

Return Home