Turing Machines with Sublogarithmic Space
Turing Machines with Sublogarithmic Space
Journal of Automata, Languages and Combinatorics - Special issue: selected papers of the second internaional workshop on Descriptional Complexity of Automata, Grammars and Related Structures (London, Ontario, Canada, July 27-29, 2000)
Lower Space Bounds for Randomized Computation
ICALP '94 Proceedings of the 21st International Colloquium on Automata, Languages and Programming
FCT '95 Proceedings of the 10th International Symposium on Fundamentals of Computation Theory
SOFSEM '00 Proceedings of the 27th Conference on Current Trends in Theory and Practice of Informatics
Formal languages and their relation to automata
Formal languages and their relation to automata
The reduction of two-way automata to one-way automata
IBM Journal of Research and Development
Hierarchies of memory limited computations
FOCS '65 Proceedings of the 6th Annual Symposium on Switching Circuit Theory and Logical Design (SWCT 1965)
On probabilistic pushdown automata
Information and Computation
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We examine various pushdown automaton variants that are architecturally intermediate between the one-way PDA and the two-way PDA (2PDA), where leftward moves of the input head can only reset it to the left end of the tape, and some component of the machine configuration may be "forgotten", that is, reset to its initial value, whenever such a move is performed. Most of these model variants are shown to be equivalent in power to either the 2PDA or the one-way PDA. One exception is the Resettable Pushdown Automaton (RPDA), where the stack contents are lost every time the input is reset, and which we prove to be intermediate in power between the PDA and the 2PDA. We give full characterizations of the classes of languages recognized by both the deterministic and the nondeterministic versions of the RPDA.