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Unformatted text preview: CSE 105: Automata and Computability Theory Winter 2011 Homework #6
Due: Tuesday, March 8th, 2011 Problem 1 Give a mapping function f showing that ETM ≤m L, where ETM is the emptyness problem for Turing machines and L is the language
M, w M is a Turing machines and L(M ) = {w} . Explain why your choice of f gives a correct mapping reduction.
Problem 2 Show that if L ≤m ∅ then L = ∅. (As usual, ∅ is the empty language.)
Problem 3 Let L be the language
G1 , G2 G1 and G2 are CFGs and L(G1 ) ≤m L(G2 ) Show that L is undecidable.
Hint: You’ll want to work with ALLCFG , not EQCFG . . ...
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This note was uploaded on 08/31/2011 for the course CSE 105 taught by Professor Paturi during the Spring '99 term at UCSD.
 Spring '99
 Paturi

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