Notes on Complexity Theory Last updated : September 14 , 2011 Lecture 5
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چکیده
We know that there existNP-complete languages. Assuming P 6= NP, any NP-complete language lies in NP \ P. Are there languages that are neither in P nor NP-complete? Ladner’s theorem tells us that there are. As some intuition for Ladner’s theorem, take some language L ∈ NP \ P. Using padding, we will make L “easy enough” so that it can’t be NP-complete, while keeping it “hard enough” so it is not in P either. Say the best algorithm for deciding L runs in time nlog n for concreteness. (The same argument, though messier, works as long as the best algorithm deciding L requires super-polynomial time.) Define
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تاریخ انتشار 2011