ab and (ab)* same or not?

Question

are a*b* and (ab)* the same language? I am trying to make nfa for a*b*

`a*b*` not the same as `(ab)*`. You can have the word `a` with the first, but cannot with the second. — Eraklon, Mar 25 '20 at 21:16
I'm voting to close this question as off-topic because it belong on cs.stackexchange.com . — einpoklum, Mar 25 '20 at 21:18

score 2 · Accepted Answer · answered Mar 25 '20 at 21:20

These two regular expressions define different languages.

a*b* matches any number of repetitions (including zero) of a followed by any number of repetitions (including zero) of b. For example aaabb.

(ab)* matches any number of repetitions (including zero) of the ab sequence, for example abab.

The empty string and ab are the only two words that match both regular expressions.

score -1 · Answer 2 · edited Mar 18 '23 at 07:47

-1

a*b* is the same of (a+b)* but not the (ab)*

edited Mar 18 '23 at 07:47

Wai Ha Lee

answered Mar 17 '23 at 14:40

Sankar Pal

a*b* and (ab)* same or not?