Learn More
This paper introduces and discusses deep pushdown automata as a generalization of the classical pushdown automata. This generalization consists in allowing them to make expansions deeper in the pushdown. Based on the expansion depth, the present paper establishes an infinite hierarchy of language families that coincides with the hierarchy resulting from the(More)
The present paper suggests a new investigation area of the formal language theory—regulated automata. Specifically, it investigates pushdown automata that regulate the use of their rules by control languages. It proves that this regulation has no effect on the power of pushdown automata if the control languages are regular. However, the pushdown automata(More)