Question

Is this language regular?

 L1:{wxwR∣w,x∈{a,b}∗ and |w|,|x|>0},

wR is the reverse of string w

Please explain..

Answer 1

In this language , first and last letter will be the same either a or b 

Also whatever comes in the middle will be occupied by the X.

hence , regular expression will be $a(a+b)^+a+ b(a+b)^+b$

Comments

double check?

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@manojk sir

what?

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put w =∈ you will get everything .

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edited . check now...

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@manojk |w|>0

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@praveen sir here

$w,x\epsilon (a+b)^{*}$

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oh sorry sir missed that point.

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So what happens when x≥0 in that case it will be regular or not?? @Praveen Saini

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$(a+b)^+$ will be replaced by $(a+b)^*$