Sorting and Element Distinctness on One-Way Turing Machines

  • Authors:
  • Holger Petersen

  • Affiliations:
  • Univ. Stuttgart, FMI, Stuttgart, D-70569

  • Venue:
  • Language and Automata Theory and Applications
  • Year:
  • 2008

Quantified Score

Hi-index 0.00

Visualization

Abstract

For nondeterministic Turing machines with one work-tape and one-way input a lower time bound Ω(m2茂戮驴) on sorting mstrings of length 茂戮驴 each is shown, which matches the upper bound. For the related Element Distinctness Problem with input of the same format we prove the upper bound O(m2) if 茂戮驴 = O(m/logm), showing this problem to be easier than sorting. The bound O(m2) also holds for deterministic machines if 茂戮驴 = c+ logmwith constant c. For this problem Szepietowski has shown the bound 茂戮驴(m2logm) on deterministic Turing machines without input tape.