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Recent questions tagged context-free-language

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134
self doubt: TOC
is union of regular language and context free language always regular?
is union of regular language and context free language always regular?
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3 votes
1 answer
135
Self Doubt : Ambiguity
Why is ambiguity in regular language is decidable and not decidable in CFL ? Can you give Example?
Why is ambiguity in regular language is decidable and not decidable in CFL ? Can you give Example?
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2 votes
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142
Michael Sipser Edition 3 Exercise 2 Question 31 (Page No. 157)
Let $B$ be the language of all palindromes over $\{0,1\}$ containing equal numbers of $0's$ and $1's.$ Show that $B$ is not context free$.$
Let $B$ be the language of all palindromes over $\{0,1\}$ containing equal numbers of $0's$ and $1's.$ Show that $B$ is not context free$.$
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145
Michael Sipser Edition 3 Exercise 2 Question 25 (Page No. 157)
For any language $A,$ let $SUFFIX(A) = \{v\mid uv \in A$ $\text{for some string u\}}.$ Show that the class of context-free languages is closed under the $\text{SUFFIX operation.}$
For any language $A,$ let $SUFFIX(A) = \{v\mid uv \in A$ $\text{for some string u\}}.$ Show that the class of context-free languages is closed under the $\text{SUFFIX ope...
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147
Michael Sipser Edition 3 Exercise 2 Question 23 (Page No. 157)
Let $D = \{xy\mid x, y\in \{0,1\}^{*}$ $\text{and}$ $\mid x\mid = \mid y\mid$ $\text{but}$ $x\neq y\}.$ Show that $D$ is a context-free language$.$
Let $D = \{xy\mid x, y\in \{0,1\}^{*}$ $\text{and}$ $\mid x\mid = \mid y\mid$ $\text{but}$ $x\neq y\}.$ Show that $D$ is a context-free language$.$
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148
Michael Sipser Edition 3 Exercise 2 Question 21 (Page No. 156)
Let $\Sigma = \{a,b\}.$ Give a $CFG$ generating the language of strings with twice as many $a’s$ as $b’s.$ Prove that your grammar is correct$.$
Let $\Sigma = \{a,b\}.$ Give a $CFG$ generating the language of strings with twice as many $a’s$ as $b’s.$ Prove that your grammar is correct$.$
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149
Michael Sipser Edition 3 Exercise 2 Question 20 (Page No. 156)
Let $A/B = \{w\mid wx\in A$ $\text{for some}$ $x \in B\}.$ Show that if $A$ is context free and $B$ is regular$,$ then $A/B$ is context free$.$
Let $A/B = \{w\mid wx\in A$ $\text{for some}$ $x \in B\}.$ Show that if $A$ is context free and $B$ is regular$,$ then $A/B$ is context free$.$
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