Explain the concept of pumping lemma in automata theory.

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Explain the concept of pumping lemma in automata theory.

The pumping lemma is a fundamental concept in automata theory that is used to prove that a language is not regular. It states that for any regular language L, there exists a pumping length p such that any string s in L with length greater than or equal to p can be divided into five parts: s = xyzuv, where the following conditions hold:

1. The length of y and v combined is greater than 0.
2. The length of xy and uv combined is less than or equal to p.
3. For any non-negative integer n, the string xyⁿzuvⁿ belongs to L.

In simpler terms, the pumping lemma states that if a language is regular, then any sufficiently long string in that language can be "pumped" by repeating a portion of it any number of times and still remain in the language. If a language fails to satisfy the pumping lemma, it is not regular. The pumping lemma is a powerful tool for proving the non-regularity of languages and is widely used in automata theory.