 Pumping lemma for context-free languages

For some $p$, every sufficiently long $w$ in a context-free language has $w=uvxyz$ with $|vxy|\le p$, $|vy|>0$, and $u{v}^{i}x{y}^{i}z$ in the language for all $i\ge 0$.

The Pumping Lemma for context-free languages is a property that all context-free languages (CFLs) must satisfy. It provides a way to prove that certain languages are not context-free by demonstrating that they do not conform to the lemma's conditions.