I am trying to get my head around the Pumping Lemma to prove a language is non-regular.
I am reading the Sipser text book and he gives the following example.
Let B be the language $\{0^n 1^n | n \ge 0\}$
Let $s = 0^p 1^p$
I understand that the idea is you can split this string into xyz such that y can be pumped. It is the constraint of $|xy| \le p$ that is confusing me.
Sipser notes that due to this constraint y could not equal 01 nor could it equal 1. Why would y equaling either of those values violate the given constraint.
I am generally quite confused by the Pumping Lemma so any general advice or good resources you can recommend, I would appreciate.
Thanks!