Grand Test TOC Q15

+1 vote

S1: If X is any CFL and Y is any regular language, X ∩ Y must be regular. 

S2 : If X and Y are each CFL's and neither X nor Y is regular, thenX \cup Y must be a CFL and X ∪ Y must not be regular. 

Which of the above statement is/are CORRECT ?

A. Only S1

B. Only S2

C. Both S1 and S2

D. Neither S1 nor S2

asked Dec 10, 2019 in TOC by getgatebook (34,830 points)
reshown Dec 11, 2019 by getgatebook

2 Answers

+1 vote
Best answer

Answer : D

S1 : Take  X = a^nb^n; Y = \Sigma^* ; \,\,\,X \cap Y = X(Non-regular\,\,CFL)

S2 : Take X = a^nb^n; Y = \bar{X};\,\,\,X \cup Y = \Sigma^*  

answered Dec 11, 2019 by (7,500 points)
selected Dec 14, 2019 by getgatebook
0 votes


both are incorrect

so d is correct one.
answered Dec 11, 2019 by (34,630 points)