Recent questions tagged regular-language

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Let $\text{A/B = {w| wx ∈ A for some x ∈ B}}.$ Show that if $A$ is regular and $B$ is any language, then $\text{A/B}$ is regular.
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Let $B$ and $C$ be languages over $\sum = \{0, 1\}.$ Define $B\overset{1}{\leftarrow} C = \{w\in B|$ $\text{for some}$ $y\in C$ ... $\overset{1}{\leftarrow}$operation.
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Let $A$ be any language. Define $\text{DROP-OUT(A)}$ ... picture and a more formal proof by construction as in $\text{Theorem 1.47.}$
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For languages $A$ and $B,$ let the $\text{shuffle}$ of $A$ and $B$ be the language $\{w| w = a_{1}b_{1} \ldots a_{k}b_{k},$ ... $a_{i}, b_{i} ∈ Σ^{*}\}.$Show that the class of regular languages is closed under shuffle.
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For languages $A$ and $B,$ let the $\text{perfect shuffle}$ of $A$ and $B$ be the language$\text{{$w| w = a_{1}b_{1} · · · a_{k}b_{k},$ where ... a_{i}, b_{i} ∈ Σ$}}.$Show that the class of regular languages is closed under perfect shuffle.
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Recall that string $x$ is a $\text{prefix}$ of string $y$ if a string $z$ exists where $xz = y,$ and that $x$ is a $\text{proper prefix}$ of $y$ if in ...
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An $\text{all-NFA}$ $M$ is a $\text{5-tuple}$ $(Q, Σ, δ, q_{0}, F)$ that accepts $x\in\sum^{*}$ if every possible state that $M$ ... states is an accept state$.$ Prove that $\text{all-NFAs}$ recognize the class of regular languages$.$
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Let $C_{n} = \{x| x \text{ is a binary number that is a multiple of $n$}\}.$ Show that for each $n\geq1,$ the language $C_{n}$ is regular$.$
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Let $B_{n} = \{a^{k}| \text{$k$ is a multiple of $n$}\}.$ Show that for each $n\geq 1,$ the language $B_{n}$ is regular$.$
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Let ... $\begin{bmatrix} 0\\0 \end{bmatrix}\notin D$Show that $D$ is regular$.$
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Let ... $C$ is regular. $\text{(You may assume the result claimed in question $31$})$
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Let ... $Working with $B^{R}$ is easier. You may assume the result claimed in question $31$})$
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For any string $w = w_{1}w_{2} · · · w_{n},$ the reverse of $w,$ written $w^{R},$ is the string $w$ in reverse order$, w_{n} · · · w_{2}w_{1}.$ For any language $A,$ ... $A$ is regular$,$ so is $A^{R}.$
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Use the pumping lemma to show that the following languages are not regular.$A_{1}=\{0^{n}1^{n}2^{n}|n\geq 0\}$ ... {(Here,}$\text{$a^{{2}^{n}}$}$ $\text{means a strings of $2^{n}$ a's.)}$
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Let $B$ be any language over the alphabet $Σ.$ Prove that $B = B^{+}$ iff $BB ⊆ B.$
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For each of the following languages, give two strings that are members and two strings that are not members-a total of four strings for each part. Assume the alphabet ... $aba\cup bab$(\epsilon\cup a)b$(a\cup ba\cup bb)\Sigma^{*}$
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Give a counterexample to show that the following construction fails to prove $\text{Theorem 1.49,}$ the closure of the class of regular languages under the star operation$.$ ... $N$ does not recognize the star of $N_{1}^{'s}$ language.
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Let $L=$ {$a^nb^m:n\geq100,m\leq50$}.(a) Can you use the pumping lemma to show that L is regular?(b) Can you use the pumping lemma to show that L is not regular?Explain your answers.
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In the chain code language in Exercise 24, Section 3.1, let $L$ be the set of all $w ∈$ {$u,r,l,d$}$^*$ that describe rectangles. Show that $L$ is not a regular language.
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Suppose that we know that $L_1 ∪ L_2$ and $L_1$ are regular. Can we conclude from this that $L_2$ is regular?
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Consider the argument that the language associated with any generalized transition graph is regular. The language associated with such a graph is ... case, because of the special nature of $P$, the infinite union is regular.
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Let $P$ be an infinite but countable set, and associate with each $p ∈ P$ a language $L_p$. The smallest set containing every $L_p$ is the union ... . Show by example that the family of regular languages is not closed under infinite union.
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Are the following languages regular?(a) $L=$ {$uww^Rv:u,v,w∈ ${$a,b$}$^+$}(b) $L=$ {$uww^Rv:u,v,w∈ ${$a,b$}$^+$, $|u|\geq |v|$}
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Let $L_1$ and $L_2$ be regular languages. Is the language $L =$ {$w : w ∈ L_1, w^R ∈ L_2$ necessarily regular?
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