tut14sol

# tut14sol - L we need to design a function such that an...

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COMP 271H Design and Analysis of Algorithms 2006 Fall Semester Tutorial 14 1. General steps to prove a decision problem L NPC (a) Prove L NP Describe your certiﬁcate Give a polynomial time (in term of input size) algorithm to verify such certiﬁcate In this part, we only care about the yes-input (b) Prove L 0 p L for some L 0 NPC In theory, we can pick any L 0 . But it is easy to pick L 0 NPC which is quite similar to L . For example, if L is a graph problem, we can pick any known NPC graph problem as L 0 . After you have chosen
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Unformatted text preview: L , we need to design a function such that an input is yes/no-input of L iﬀ the transformed input is yes/no-input of L . You can show Y → Y and Y ← Y , or Y → Y and N → N . Both approaches are equivalent. • If your reduction function is reversible, then proving Y → Y is suﬃcient. Otherwise, you need to prove Y → Y and Y ← Y separately. c ± 2006 Chung Kai Lun Peter. Comments are welcomed. Email: [email protected] 1...
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## This note was uploaded on 12/09/2010 for the course ENGLISH 1303 taught by Professor May during the Spring '10 term at HKU.

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