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lfa:reg [2018/07/23 13:25] pdmatei [Definition] |
lfa:reg [2018/07/23 14:47] (current) pdmatei |
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Therefore, we have shown that **NFAs and DFAs accept the same languages**, i.e. $math[L(NFA) = L(DFA)]. In other words, if a language $math[L] is accepted by some DFA $math[M] ($math[L=L(M)]), then it can also be accepted by some NFA, and vice-versa. | Therefore, we have shown that **NFAs and DFAs accept the same languages**, i.e. $math[L(NFA) = L(DFA)]. In other words, if a language $math[L] is accepted by some DFA $math[M] ($math[L=L(M)]), then it can also be accepted by some NFA, and vice-versa. | ||
- | It remains to establish the relationshi | + | It remains to establish the relationship between $math[LR] and $math[L(DFA)] (or equivalently $math[L(NFA)]). |
- | p between $math[LR] and $math[L(DFA)] (or equivalently $math[LNFA]). | + | |
===== Equivalence between Regular Expressions and Automata ===== | ===== Equivalence between Regular Expressions and Automata ===== | ||
$justtheorem | $justtheorem | ||
- | Let $math[M] be a DFA. There exists a **regular expression** $math[E], such that $math[L(E)=L(A)]. | + | Let $math[M] be a DFA. There exists a **regular expression** $math[E], such that $math[L(E)=L(M)]. |
$end | $end | ||
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If $math[i = j], then: | If $math[i = j], then: | ||
- | * $math[R^{(0)}_{ii}] may contain **zero** transitions, hence $math[R^{(0)}_{ij} = \epsilon] | + | * $math[R^{(0)}_{ii}] may contain **zero** transitions, hence $math[R^{(0)}_{ij} = \epsilon] |
- | * $math[R^{(0)}_{ii}] may contain one transition, and the construction follows the above rules, yielding some regular expression $math[E_0]. | + | * $math[R^{(0)}_{ii}] may contain one transition, and the construction follows the above rules, yielding some regular expression $math[E_0]. |
We combine the two situations in a single one: $math[R^{(0)}_{ii} = \epsilon \cup E_0], where $math[E_0] is constructed as above. | We combine the two situations in a single one: $math[R^{(0)}_{ii} = \epsilon \cup E_0], where $math[E_0] is constructed as above. | ||