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COMP SCI 731 - Lecture 6 - Monday, Nov 20, 2000
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Today: o More sample reductions
       o Definitions of reductions and NP-completeness



Review:

- When is a problem in P?
- When is a problem in NP?
- When is a problem NP-complete?
- What does it mean for A to reduct to B?




More example reductions.  Assume SAT is NP complete.  Let's show:
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We've seen

 0) CLIQUE is NP-Complete

Let's do:

 1) 3SAT  is NP complete (SAT < 3SAT)

 2) G3C is NP complete (3SAT < G3C)

             use the gadget 

         ------------- O \
                       |   \   
                       |     O------O
                       |   /        | \
         ------------- O /          |   \
                                    |     O TRUE
                                    |    /
                                    |  /
         -------------------------- O/

        

 3) 3SAT  < HC

           use the gadgets of CLR