Tuesday, February 26, 2008

Homework 3 correction -- Problem 4

Hi -- as many of you noticed, the last part of Problem 4 does not look so doable :)

The result is in fact true -- indeed, Ω(logn) hardness for Set-Cover is known even subject to P NP. However the method illustrated probably won't cut it.

Please do one of the following instead:

1. Use this method to prove f(n)-hardness for Set-Cover, for as large a function f(n) as you can -- subject to NP not in DTIME(2o(n)) or an even better DTIME assumption.

OR

2. Prove Ω(logn)-hardness for Set-Cover assuming NP not in BPTIME(npolylogn) -- using any method.

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