Regular Language


Q11.

Consider the languages L_{1}=\phi abd L_{2}=\{a\}. Which one of the following represents L_{1} L_{2}^{*} \cup L_{1}^{*}?
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Q12.

Consider the following statements. I. If L_1\cup L_2 is regular, then both L_1 \; and \; L_2 must be regular. II. The class of regular languages is closed under infinite union. Which of the above statements is/are TRUE?
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Q13.

A language L satisfies the Pumping Lemma for regular languages, and also the Pumping Lemma for context-free languages. Which of the following statements about L is TRUE?
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Q14.

Which one of the following is TRUE?
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Q15.

Let \Sigma=\left\{0,1\right\}, L = \Sigma^* \text{ and } R=\left\{0^n1^n \mid n \gt 0\right\} then the languages L \cup R and R are respectively
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Q16.

Let L be a regular language. Consider the constructions on L below: I. \text{repeat} (L) = \{ww \mid w \in L\} II. \text{prefix} (L) = \{u \mid \exists v : uv \in L\} III. \text{suffix} (L) = \{v \mid \exists u: uv \in L\} IV. \text{half} (L) = \{u \mid \exists v: | v | = | u | \text{ and } uv \in L\} Which choice of L is best suited to support your answer above?
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Q17.

Let L be a regular language. Consider the constructions on L below: I. \text{repeat} (L) = \{ww \mid w \in L\} II. \text{prefix} (L) = \{u \mid \exists v : uv \in L\} III. \text{suffix} (L) = \{v \mid \exists u: uv \in L\} IV. \text{half} (L) = \{u \mid \exists v: | v | = | u | \text{ and } uv \in L\}Which of the constructions could lead to a non-regular language?
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Q18.

Which of the following is true?
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Q19.

If s is a string over (0+1)*, then let n_0 (s) denote the number of 0's in s and n_1 (s) the number of 1's in s. Which one of the following languages is not regular?
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Q20.

Which of the following statements about regular languages is NOT true ?
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