Toc -regular

Question

Which of the following statements are true?

1)The union of 2 non regular languages is non regular.

2)The intersection of 2 non regular languages is non regular.

a) 1 only

b) 2 only

c)both

d)none

Answer 1

Both statement are false .

Comments

In this case we are getting regular...but there can be chance that we can get non regular also...ryt??

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Yes possible .

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@ kunal chalotra,

Question is not asking for always true. 

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for both it should be may or may not regular..

here wat we should consider...true or false??? (#ambiguous#)

plz answer

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 Kapil Things are either true or false.If you can prove it false then it is false.you can't say it is partially true so it is true.

Answer 2

The union of 2 non regular languages is non regular =True. since non regular i.e. i assume csl is closed under union.

The intersection of 2 non regular languages is non regular.= true , since non regular i.e. i assume csl is closed under intersection.

both

Comments

resilientknight yes 0^m1^m2^m and 0^m1^m for m >0 is non regular but intersection is phi .

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@anirudh sir: 1)if question is given "always true" then will it be "none"?

2) can the union of 2 non regular language be sigma *? if it is then it will be regular?

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yes