ISRO2015-43

Question

Let $R_1$ and $R_2$ be regular sets defined over the alphabet, then

• A. $ R_1 \cap R_2$ is not regular
• B. $R_1 \cup R_2$ is not regular
• C. $\Sigma^* - R_1$ is regular
• D. $R_1^*$ is not regular

Answer 1

option C is correct

Regular sets are closed under union, intersection, complement, and kleen closure

But regular sets are not closed under infinite union

Answer 2

"Regular languages are closed under Intersection, Union ,Kleens Closure ,Compliment"

According to this point option C is perfect

Comments

Sir  can you give example where
$\sum*   - R1$ is not regular

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∑∗−R1 is regular, this statement is true, not false.

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Oh soory Sir, i didn't read the options carefully

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ok sir