# Why do PDAs always halt?

Can’t a PDA get stuck in a cycle of blank transitions?

Should the implementation detect such cycles and do something about them? That seems quite complex to consider all the edge cases.

Does the answer vary for nondeterministic PDAs?

• Have you checked posts about "PDA halt? May 5 at 22:09
• They don't always halt. Even $\epsilon$-NFAs don't always halt. May 6 at 12:13