How can we reverse a regular expression?

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Consider the following regular expressions:

I. 0(0+1)*

II. 0* 10*1(0 +1)*

III (0+10)*(1+€)

IV.[(0*10* 10*)* +0*]10*

A language L whose regular expression is r is said to be reverse isomorphic if L(r)= L(r^R). How many of the above regular expressions are reverse isomorphic?

I. 0(0+1)*

II. 0* 10*1(0 +1)*

III (0+10)*(1+€)

IV.[(0*10* 10*)* +0*]10*

A language L whose regular expression is r is said to be reverse isomorphic if L(r)= L(r^R). How many of the above regular expressions are reverse isomorphic?

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Well, what we 'think' may not always be correct. If you say that II is reverse isomorphic and the others are not, you must provide a justification as to why II is, and the others aren't.

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given regular expressions are along with there meaning

I. 0(0+1)* all strings starting wiith 0

II. 0* 10*1(0 +1)* all strings containing atleast two 1's

III (0+10)*(1+€) all strings containing no consecutive 1's

IV.[(0*10* 10*)* +0*]10* now i don't know exactly what this is representing ,but it does not necessarily start with 1

Reversed expressions can be writtten as below

1.(0+1)*0 all strings ending wiith 0

2.(0 +1)*10*10* all strings containing atleast two 1's

3.(1+€) (0+01)* all strings containing no consecutive 1's

4. 0*1[(0*10* 10*)* +0*]

@Lakshay Kakkar thanks for rectifying ,pls verfify now that 2nd and 3rd are reverse isomorphic and what about 4th?

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You have not reversed the 3rd regular expression correctly. And the exact same mistake has been repeated in 4th aswell.

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@Lakshay Kakkar 2nd is reverse isomorphic I have written above

and according to you what should be correct reversed expressions for 3rd and 4th pls tell

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