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+1 vote
178 views
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,

VIshnu
asked in Theory of Computation by (23 points)
retagged by | 178 views

1 Answer

+1 vote
(ab*)*
L=(epsilon,a,aa,aaaa,ab,abb,abab,abbbbbbbab,.......)
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)
0
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.
0
suppose if it would have been only (ab)*....then what could be the language...epsilon,ab,abab,ababab....so on

now just put closure on every b....thats it....
any more doubt brother?
+1
see this u will get the bigger picture

ab*,ab*ab*,ab*ab*ab*,.....

now try to expand each one
say ab*=a,ab,abb,abbbbb...
ab*ab*=aa,aba,abab,abba,...

this way u can do
0
language starting with a and ending with a or b (including epsilon), right??

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