CSE 472/572, Spring 2002

HW #8: KNOWLEDGE REPRESENTATION

  1. R&N, Ch. 8, p. 262: #8.8

  2. Translate each of the following sentences into the language of first-order predicate calculus. Be sure to give your syntax and semantics.

  3. Here is the syntax and semantics for some generic SNePS case frames.

    EnglishexamplelogicSNePS example
    x is a YJohn is a computer scientist Y(x)
    or:
    x \epsilon Y
           M     
          / \
         /   \
      member class
       /       \
      /         \
     |           |
     V           V
     x           Y
    
            M
           / \
          /   \
       member class
        /       \
       /         \
      |           |
      V           V
     John      computer
              scientist
    x is YJohn is rich Y(x)
           M
          / \
         /   \
     object property
       /       \
      /         \
     |           |
     V           V
     x           Y
            M
           / \
          /   \
      object property
        /       \
       /         \
      |           |
      V           V
     John        rich
    x stands in the relation R to y John is taller than Ann R(x,y)
            M
           /|\
          / | \
         /  |  \
      arg1 rel arg2
       /    |    \
      /     |     \
     |      |      |
     V      V      V
     x      R      y
             M
            /|\
           / | \
          /  |  \
       arg1 rel arg2
        /    |    \
       /     |     \
      |      |      |
      V      V      V
     John  taller  Ann
            than      
    (This generalizes to:)R(t1,...,tn)
            M
           /|\
          / | \
         /  |  \
        /   |   \
      rel arg1..argn
      /     |     \
     /      |  ..  \
    |       |       |
    V       V       V
    R       t1  ..  tn
    All As are BsAll dogs are animals \forall x [A(x) => B(x)]
                      M
                     /| \
                    / |  \
                   /  |   \
                  /   |    \
                ant   |     cq
                /     |      \
               /      |       \
              |     forall     |
              V       |        V
             P1       |       P2
             /\       |       /\
            /  \      |      /  \
           /    \     |     /    \
       class  member  |  member  class
         /        \   |   /        \
        /          \  |  /          \
       /            \ | /            \
      /              \|/              \
     |                |                |
     V                V                V
     A                x                B
    [dog]                       [animal]
    

    Here's an extended example, with 2 corresponding, but slightly different, SNePS networks (one with ``default'' arc labels, as above, and one with more descriptive arc labels):

    John bought a book from Mary

                    M1----time--->past
                   / \
                  / | \
                 / / \ \
                /  | |  \
               /  /   \  \
              /   |   |   \
             /   /     \   \
           rel  arg1  arg2 arg3
           /    /       \    \
          /     |       |     \
         /     /         \     \
        /      |         |      \
       /      /           \      \
      |      |             |      |
      V      V             V      V
     buy    John           B1    Mary
                           ^
                           |
                           |
                         member
                           |
                           |
                          M2---class--->book





                    M2----time--->past
                   / \
                  / | \
                 / / \ \
                /  | |  \
               /  /   \  \
              /   |   |   \
             /   /     \   \
           act agent object from
           /    /       \    \
          /     |       |     \
         /     /         \     \
        /      |         |      \
       /      /           \      \
      |      |             |      |
      V      V             V      V
     buy    John           B1    Mary
                           ^
                           |
                           |
                         member
                           |
                           |
                          M2---class--->book

    Now, translate each of the sentences from the previous question into SNePS. Be sure to give your syntax and semantics.

DUE: AT THE START OF LECTURE: WEDNESDAY, MAY 1



Copyright © 2002 by William J. Rapaport (rapaport@cse.buffalo.edu)
file: 572/S02/hw08.12ap02.html