several additions to the class page

[Subbarao Kambhampati <rao@parichaalak.eas.asu.edu>]

Folks:
 
 I added the following

 --Updated version of the slides for this week (added a couple of
slides covering the non-slide discussion in todays class)

 --added problem 3 to Homework 4 (which is about writing SAT
encodings) 

Rao
[Mar  6, 2003]