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+1 vote
Hi Experts,

Can anyone please tell me the strings present in regular expression (ab*)*

My doubt is whether (ab*)* can have any combination of the strings in RE ab* like in the following language.

L={a,ab,abb}* = {aab,aabb,abba,ababb,..}

Here abba is obtained by combining abb and a.

Please tell me whether my understanding is right.

Thanks in advance,

asked in Theory of Computation by (23 points)
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1 Answer

+1 vote
from outer closure u can get any no of times ab*.....from here u can get any number of b with one a...or even any number of a if we make inner b* as epsilon each time and take outer closure into consideration..
answered by Boss (19.7k points)
I got the ab* part.What I wanted to know was how do we apply kleene closure to ab*.

ab* = {€,a,ab,abb,..}

Can you please tell me how to apply kleene closure to ab*.i.e.the outer kleene closure.
suppose if it would have been only (ab)*....then what could be the language...epsilon,ab,abab, on

now just put closure on every b....thats it....
any more doubt brother?
see this u will get the bigger picture


now try to expand each one
say ab*=a,ab,abb,abbbbb...

this way u can do
language starting with a and ending with a or b (including epsilon), right??

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