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Showing papers by "Juris Hartmanis published in 1991"


Journal ArticleDOI
TL;DR: This paper gives a relativized counterexample to the One-way Conjecture by constructing a relatvized world that has nonisomorphic NP-complete sets, but lacks one-way functions.

61 citations


Journal ArticleDOI
29 Mar 1991
TL;DR: This paper shows that, for a slightly modified Turing machine model, the low level deterministic and nondeterministic space bounded complexity classes are different and shows that Savitch and Immerman-Szelepcsenyi theorems do not hold in the range lg lg n to lG n.
Abstract: In this paper we review the key results about space bounded complexity classes, discuss the central open problems and outline the relevant proof techniques. We show that, for a slightly modified Turing machine model, the low level deterministic and nondeterministic space bounded complexity classes are different. Furthermore, for this computation model, we show that Savitch and Immerman-Szelepcsenyi theorems do not hold in the range lg lg n to lg n. We also discuss some other computation models to bring out and clarify the importance of space constructibility and establish some results about these models. We conclude by enumerating a few open problems which arise out of the discussion.

42 citations