EXTRA-CREDIT HOMEWORK #10

SNePS

This HW is optional, and will count for extra credit (it will replace your lowest HW grade). I recommend that you try it before the final exam, even if you decide not to hand it in. I will post the answers after it is due.

For this HW, you might find it helpful to re-read Martins 2002: 172-192. Then do the following exercises adapted from Martins 2002, pp. 211-212, #5,6,7,8, together with a few extra questions:

1. (Adapted from Martins 2002: 211, #5)
   SNePS does not allow the following representation for the statement "Tweety is a bird". Explain the reason for this decision.

   Tweety

   |
   isa
   |
   V
   

   bird

   ---

2. (Adapted from Martins 2002: 211, #6)
   1. Explain the differences between (a) the SNePS representation shown below for the statement "John is a man" and (b) the one from problem 1, above.

   2. Why is the representation below legal (even though Martins 2002 calls it "bad")?

      M1!

      |
      is-a-man
      |
      V
      

      John

   3. Why does Martins call this "bad"?

   4. Give a better SNePS representation, and explain why it's better.

   ---

   For problems 3 and 4, you might try to represent the propositions using FOL.

   ---

3. (Adapted from Martins 2002: 212, #7)
   What does the following represent? (Assume that M1 and M2 are SNePS proposition-nodes.)
   (assert min 1 max 1 arg M1 arg M2)

   ---

4. (Adapted from Martins 2002: 212, #8)
   What does the following represent? (Assume that M1,...,Mn are SNePS proposition-nodes.)
   (assert min 0 max 0 arg M1 ... arg Mn)

   (Note that in the SNePSUL renditions of 3 and 4, there is no need to include the parameters "2" and "n" that appear in the notation in Martins 2002.)

   ---

5. Give SNePSUL representations of the following sentences, along with the syntax and semantics of the case frames that you use. You may either draw networks (by hand is easiest), or show the SNePSUL code, or actually type them in to SNePS and use "show" to draw the networks for you.
   1. Mary believes everything that Bill believes.
   2. Mary believes nothing that Bill believes.
   3. It is not the case that Mary believes everything that Bill believes.

DUE: AT THE BEGINNING OF LECTURE, MONDAY, MAY 2