Towards Regular Languages over Infinite Alphabets
MFCS '01 Proceedings of the 26th International Symposium on Mathematical Foundations of Computer Science
Parallel and Sequential Optical Computing
OSC '08 Proceedings of the 1st international workshop on Optical SuperComputing
On Alternating Phrase-Structure Grammars
Language and Automata Theory and Applications
Two Ways of Introducing Alternation into Context-Free Grammars and Pushdown Automata
IEICE - Transactions on Information and Systems
Alternation as a programming paradigm
PPDP '09 Proceedings of the 11th ACM SIGPLAN conference on Principles and practice of declarative programming
Efficient probabilistically checkable debates
APPROX'11/RANDOM'11 Proceedings of the 14th international workshop and 15th international conference on Approximation, randomization, and combinatorial optimization: algorithms and techniques
Optical computing and computational complexity
UC'06 Proceedings of the 5th international conference on Unconventional Computation
Lower bounds on the computational power of an optical model of computation
UC'05 Proceedings of the 4th international conference on Unconventional Computation
Upper bounds on the computational power of an optical model of computation
ISAAC'05 Proceedings of the 16th international conference on Algorithms and Computation
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We define alternating Turing Machines which are like nondeterministic Turing Machines, except that existential and universal quantifiers alternate. Alternation links up time and space complexities rather well, in that alternating polynomial time equals deterministic polynomial space, and alternating linear space equals deterministic exponential time. Such considerations lead to a two-person game complete in polynomial time, and other games complete in exponential time. We also find that computability on a parallel processing machine is a rather rugged notion, and present two parallel processing models that are polynomially equivalent in their running times. We also show that while n-state alternating finite automata accept only regular sets that can be accepted by 22n-O(logn) state deterministic automata, alternating pushdown automata accept all languages accepted by Turing machines in deterministic exponential time.