Automata, Languages and Programming

Volume 85 of the series Lecture Notes in Computer Science pp 374-384


Symmertric space-bounded computation (extended abstract)

  • Harry R. LewisAffiliated withAiken Computation Laboratory, Harvard University
  • , Christos H. PapadimitriouAffiliated withDepartment of Electrical Engineering and Computer Science, Massachusetts Institute of Technology

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A symmetric Turing machine is one whose "yields" relation between configurations is symmetric. The space complexity classes for such machines are found to be intermediate between the corresponding deterministic and nondeterministic space complexity classes. Certain natural problems are shown to be complete for symmetric space complexity classes, and the relationship of symmetry to determinism and nondeterminism is investigated.