Reducing Deep Pushdown Automata and Infinite Hierarchy

Automata Theory, Top-Down Parser, Bottom-Up Parser, Deep Pushdown Automata, Infinite hierarchy, Reduction Operation, Shift Operation

This contribution presents reducing variant of the deep pushdown automata. Deep pushdown automata is a new generalization of the classical pushdown automata. The basic idea of the modification consists of allowing these automata to access more deeper parts of pushdown and reducing strings to non-input symbols in the pushdown. It works similarly to bottom-up analysis simulation of context-free grammars in the classical pushdown automata except it reads the input from the right to the left. Further, this paper presents results concerning the equivalence of reducing deep pushdown automata with n-limited state grammars and infinite hierarchy of language families based on that and one open problem.