Input-Driven Double-Head Pushdown Automata

Markus Holzer
(Institut für Informatik, Universität Giessen)
Martin Kutrib
(Institut für Informatik, Universität Giessen)
Andreas Malcher
(Institut für Informatik, Universität Giessen)
Matthias Wendlandt
(Institut für Informatik, Universität Giessen)

We introduce and study input-driven deterministic and nondeterministic double-head pushdown automata. A double-head pushdown automaton is a slight generalization of an ordinary pushdown automaton working with two input heads that move in opposite directions on the common input tape. In every step one head is moved and the automaton decides on acceptance if the heads meet. Demanding the automaton to work input-driven it is required that every input symbol uniquely defines the action on the pushdown store (push, pop, state change). Normally this is modeled by a partition of the input alphabet and is called a signature. Since our automaton model works with two heads either both heads respect the same signature or each head owes its own signature. This results in two variants of input-driven double-head pushdown automata. The induced language families on input-driven double-head pushdown automata are studied from the perspectives of their language describing capability, their closure properties, and decision problems.

In Erzsébet Csuhaj-Varjú, Pál Dömösi and György Vaszil: Proceedings 15th International Conference on Automata and Formal Languages (AFL 2017), Debrecen, Hungary, September 4-6, 2017, Electronic Proceedings in Theoretical Computer Science 252, pp. 128–142.
Published: 21st August 2017.

ArXived at: http://dx.doi.org/10.4204/EPTCS.252.14 bibtex PDF
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