A note on some simultaneous relations among time, space, and reversal for single work tape nondeterministic turing machines

Etsuro Moriya, Shigeki Iwata, Takumi Kasai

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Simultaneous resource bounded complexity classes for nondeterministic single worktape off-line Turing machines are considered such as time-space bounded classes, denoted by NTISP1(T, S), reversal-space bounded classes, denoted by NRESP1(R, S), and time-reversal bounded classes, denoted by NTIRE1(T, R). It is shown that NRESP1(R(n), S(n)) contains NTISP1(S(n), R(n)) and is contained in NTISP1(R(n) S(n)n2 log n, R(n) log n). The following corollaries follow: (1) the affirmative solution to the nondeterministic single worktape version of the NC = ? SC problem, NTIRE1(poly, polylog) = NTISP1(poly, polylog), and (2) a reversal-space trade-off, NRESP1(polylog, poly) = NRESP1(poly, polylog).

Original languageEnglish
Pages (from-to)179-185
Number of pages7
JournalInformation and control
Issue number2-3
Publication statusPublished - 1986
Externally publishedYes


ASJC Scopus subject areas

  • Engineering(all)

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