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Unformatted text preview: Sep. 10, 2010 (Friday) Chapter 1: Regular Languages 6.4 Equivalence between NFA and DFA Since a DFA is a special type of NFA, it seems that NFAs are more powerful than DFAs. But surprisingly, they have the same power in terms of the class of languages recognized by them; that is, both DFAs and NFAs recognize the same class of languages. 6.4.1 Converting an NFA without transition to an equivalent DFA We say that two machines are equivalent to each other, if they recognize the same language. Basic Idea: To find an equivalent DFA of an NFA, we design a DFA that simulates how an NFA accepts or rejects an input string. Consider how the following NFA accepts or rejects input string ab . b 1 2 a,b a b a,b a This NFA accepts string ab . b 1 1 2 a b a b Three steps to design an equivalent DFA. Step 1: In order to simulate this NFA, we remember the current state of each copy of this NFA after reading an input symbol....
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- Spring '10
- Following, Equivalence, DFA Records