Seperating Complexity Classes Related to Certain Input Oblivious Logarithmic Space-Bounded Turing Machines

Uncountable classical and quantum complexity classes

Polynomial–time constant–space quantum Turing machines (QTMs) and logarithmic–space probabilistic Turing machines (PTMs) recognize uncountably many languages with bounded error (Say and Yakaryılmaz 2014, arXiv:1411.7647). In this paper, we investigate more restricted cases for both models to recognize uncountably many languages with bounded error. We show that double logarithmic space is enough...

Separating the eraser Turing machine classes I + , NIL , , co - N ! + _ and P , Matthias Krause

Krause, M., C. Meinel and S. Waack, Separating the eraser Turing machine classes, Theoretical Computer Science 86 (1991) 267-275. By means of exponential lower and polynomial upper bounds for read-once-only n-branching programs we separate the logarithmic space-bounded complexity classes L,, NL,, co-NL, and P, for eraser Turing machines.

Separating Complexity Classes Using Autoreducibility

A set is autoreducible if it can be reduced to itself by a Turing machine that does not ask its own input to the oracle. We use autoreducibility to separate the polynomial-time hierarchy from polynomial space by showing that all Turing-complete sets for certain levels of the exponential-time hierarchy are autoreducible but there exists some Turing-complete set for doubly exponential space that ...

On Equivalence of Nondeterministic and Unambiguous Logarithmic Space Bounded Turing Machines

Reversal complexity revisited

We study a generalized version of reversal bounded Turing machines where, apart from several tapes on which the number of head reversals is bounded by r(n), there are several further tapes on which head reversals remain unrestricted, but size is bounded by s(n) (where n denotes the input length). Recently [9,10], such machines were introduced as a formalization of a computation model that restr...