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For even no a's  RE  over  {a,b}  

1) (b*ab*ab*)* + b*  

2) (b*ab*ab*)*.b*  

3) both are equal?

which one is correct?
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1 Answer

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$(b^*ab^*ab^*)^*+b^* \equiv (b^*ab^*ab^*)^*b^* \equiv b^*(b^*ab^*ab^*)^* \equiv b^*(ab^*ab^*)^* \equiv (b^*ab^*a)^*b^*$

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