Two-Tape Simulation of Multitape Turing Machines

  title={Two-Tape Simulation of Multitape Turing Machines},
  author={F. C. Hennie and Richard Edwin Stearns},
  journal={J. ACM},
It has long been known that increasing the number of tapes used by a Turing machine does not provide the ability to compute any new functions. On the other hand, the use of extra tapes does make it possible to speed up the computation of certain functions. It is known that a square factor is sometimes required for a one-tape machine to behave as a two-tape machine and that a square factor is always sufficient. The purpose of this paper is to show that, if a given function requires computation… 

Time Complexity of Tape Reduction for Reversible Turing Machines

It is shown that the structure of reversible time complexity classes mirrors that of irreversible complexity theory, with a similar hierarchy, and that identical results hold for multitape RTMs.

On restricted turing computability

  • E. Glinert
  • Computer Science
    Mathematical systems theory
  • 2005
Theorems are proved concerning the hierarchy of complexity classes of binary sequences which is obtained by bounding simultaneously both the time T( n) and the amount of tape L(n) which a Tnring machine may use to compute its output sequence; among these is a result on the maximum increase necessary in the time and tape bounding functions.

Computational Complexity of One-Tape Turing Machine Computations

It is shown, among other things, that it is recursively undecidable how much time is required to recognize a nonregular context-free language on a one-tape Turing machine.

Turing Machines with a Schedule to Keep

Deterministic Multitape Automata Computations

On Time Versus Space

The context-sensitive languages cannot be recognized in linear time by deterministic multitape Turing machines, and are strictly contained in the class of languages recognized by Turing machines of tape complexity.

Multi-tape and infinite-state automata—a survey

A survey of machines which are more powerful than finite automata and less powerful than general Turing machines is presented. It is felt that the machines in this category are as closely related to

Diagonalization of Polynomial-Time Turing Machines Via Nondeterministic Turing Machine

It is obtained that there is a language L d not accepted by any polynomial-time deterministic Turing machines but accepted by a nondeterministic Turing machine working within O ( n k ) for any k ∈ N 1 .



Real-Time Computation and Recursive Functions Not Real-Time Computable

  • H. Yamada
  • Computer Science
    IRE Trans. Electron. Comput.
  • 1962
As an attempt to investigate a general theory of real-time computability in digital computers, a subclass of Turing machines is formally introduced together with some classes of functions that are

On computable numbers, with an application to the Entscheidungsproblem

  • A. Turing
  • Computer Science
    Proc. London Math. Soc.
  • 1937
This chapter discusses the application of the diagonal process of the universal computing machine, which automates the calculation of circle and circle-free numbers.

faster than some constant times T(n) log T(n), then there is some computing operation that can be carried out within the bound U(n) but not within the bound : T(n)

  • faster than some constant times T(n) log T(n), then there is some computing operation that can be carried out within the bound U(n) but not within the bound : T(n)


  • 1965