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Unformatted text preview: Assignment 4. CS341, Spring 2009 Distributed Tuesday, July 7, due 3pm July 23, 2009. Hand in to the assignment boxes on the 3rd floor of MC. 1. (15 marks) Prove, by reduction, that the following problems are unsolvable. • Given input P, decide if P halts on some inputs. That is, there is an input w such that P halts on w. • Given input P, decide if P outputs “You got 100 in CS341” on input “What is my CS341 score?”. • Given input P, decide if the set of inputs accepted by P is finite. Hint: reduction from the Halting problem. 2. (10 marks) Prove that if A is unsolvable, then ¯ A = Σ * A is also unsolvable. 3. (10 marks) Show the 2SAT problem is polynomial time solvable. You get 5 marks for a polynomial time algorithm and 10 marks for a linear time algorithm. 4. (10 marks) Prove the following claims. • NP = P if and only if coNP = P. • If A ∈ NP, then A can be solved in polynomial space by a deterministic algorithm....
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This note was uploaded on 10/23/2009 for the course CS 341 taught by Professor ? during the Spring '09 term at Waterloo.
 Spring '09
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