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Unformatted text preview: University of Central Florida School of Computer Science COT 4210 Spring 2004 Prof. Rene Peralta Answers to Homework 4 1. Construct a PDA that accepts the set of palindromes over Σ = { a, b } . Use the notation of section 8.1 of the text. answer: 2. The Pumping Lemma for Regular Languages, as stated in Theorem 7.6.3 of the text (Theorem 9 in Prof. Workman’s notes), says that a longenough word z in a regular language can be “pumped” somewhere inside a prefix of z . I have argued in class that restricting the lemma to a prefix is unnecessary. State the more general pumping lemma. (You do not need to prove it, but you must state it precisely). answer: Here is one possible wording: If • L is a regular language over the alphabet Σ; and • L is accepted by a DFA with α states; and • u, v, w are strings in Σ * such that uvw ∈ L and α ≤  v  , 1 then there exists a decomposition rst of v such that s 6 = λ and urs i tw ∈ L for all i ≥ 0. 3. For each language in exercise 12, section E, of Prof. Workman’s notes answer the following....
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This note was uploaded on 06/09/2011 for the course COT 4210 taught by Professor Staff during the Spring '08 term at University of Central Florida.
 Spring '08
 Staff
 Computer Science

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