Space bounded computations: review and new separation results

Desh Ranjan, Richard Chang, Juris Hartmanis
1991 Theoretical Computer Science  
Ranjan, D., R. Chang and J. Hartmanis, Space bounded computations: review and new separation results, Theoretical Computer Science 80 (1991) 289-302. In this paper we review the key results about space bounded complexity classes, discuss the central open problems and outline the prominent proof techniques. We show that, for a slightly modified Turing machine model, low level deterministic and nondeterministic space bounded complexity classes are different. Furthermore, for this computation
more » ... , we show that Savitch's theorem and the Immerman-Szelepcs~nyi theorem do not hold in the range Ig Ig n to Ig tt We also present other changes in the computation model which bring out and clarify the importance of space constructibility. We conclude by enLmerating open problems which arise out of the discussion.
doi:10.1016/0304-3975(91)90391-e fatcat:xxm3hj5hwncsre7kavd4wbptbq