Regulated Nondeterminism in PDAs: The Non-Regular Case
Tomáš Masopust · NCMA · 2009
In this paper, we discuss pushdown automata which can make a nondeterministic decision only if the pushdown content forms a string that belongs to a given control language. It proves that if the control language is linear and non-regular, then the computational power of pushdown automata regulated in this way is increased to the power of Turing machines. Naturally, checking the pushdown content in each computational step is not practically efficient. Therefore, we also prove that two checks of the form of the pushdown content during any computation are sufficient for these automata to be computationally complete. Finally, some descriptional complexity results are discussed.