Question

Can you explain what this language is in simple terms

{wtw | w, t ∈ {0,1}⁺ }

What does the + mean, please give examples of the language.

Answer 1

here + means one or more instance of given set

A+ means, one or more occurance of that.

Languages can be regular and non regular. also it can be context free, context sensitive.

here the grammar given says that it can accepts the string of 0's and 1's having minimum length of 3.

for example following is the valid strings accepted by the grammar is

000, 111, 010, 101, 110010 and so on.

here + is called positive clouser.

Hope it helps. doubts are welcomed in the form of comments.