Context Free Languages and Pushdown Automata. اثبات مستقل از متن بودن یک زبان ( PDA ) Prove that the class of Context-Free Languages is closed under MissingMiddle,

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Presentation transcript:

Context Free Languages and Pushdown Automata

اثبات مستقل از متن بودن یک زبان ( PDA ) Prove that the class of Context-Free Languages is closed under MissingMiddle, where, assuming L is over the alphabet Σ, Suppose that A and B are regular languages. Prove that the following language is context free:

اثبات مستقل از متن بودن یک زبان ( CFG )

اثبات مستقل از متن بودن یک زبان

Class of context free languages is: closed under union concatenation iteration(*) intersection with a regular language the reverse operation Not closed under intersection complementation خواص بسته بودن

اثبات مستقل از متن نبودن یک زبان The language of all palindromes over {0, 1} that contain the same number of 0s and 1s. L = { 1 n^2 | n a positive integer } L = {a p b q c max(p,q) } L = {ww | w in {0,1}*}

اثبات مستقل از متن نبودن یک زبان The set of all strings with the unary alphabet {#} with length a perfect square. The set of all strings with the unary alphabet {#} with length a prime number.

مسائل گوناگون Let L be some regular set in which all strings happen to have length equal to a multiple of three. Let Twist3(L) be the set of all strings in L where every three symbols are reversed. For example if L = {aag, cttgta, ttggagagc,...} then Twist3(L) = {gaa, ttcatg, gttgagcga,...}. Explain why Twist3(L) is a CFL.

مسائل گوناگون