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Question 52Asked in UGC NET Computer Science, June 2017 (Paper II & III, Selected Questions)

Given the following statements : (A) A class of language that is closed under union and complementation has to be closed under intersection

Given the following statements : (A) A class of language that is closed under union and complementation has to be closed under intersection (B) A class of language that is closed under union and intersection has to be closed under complementation Which of the following options is correct?
  1. ABoth (A) and (B) are false
  2. BBoth (A) and (B) are true
  3. C(A) is true, (B) is false
  4. D(A) is false, (B) is true
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Correct answer: (C) (A) is true, (B) is false

Explanation

(A) is true by De Morgan's law: A ∩ B = (A' ∪ B')'. (B) is false: recursively enumerable languages are closed under union and intersection but not under complementation.

From UGC NET Computer Science PYQ, June 2017 (Paper II & III, Selected Questions)

This is question 52 of UGC NET Computer Science PYQ, June 2017 (Paper II & III, Selected Questions). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.