Why is {a^nb^n | n >= 0} not regular?
What you’re looking for is Pumping lemma for regular languages. Here is an example with your exact problem: Examples: Let L = {ambm | m ≥ 1}. Then L is not regular. Proof: Let n be as in Pumping Lemma. Let w = anbn. Let w = xyz be as in Pumping Lemma. Thus, xy2z … Read more