Is Wolfram and Cook's (2,5) Turing machine really universal?
Formal Languages and Automata Theory
2012-09-03 v1 Logic in Computer Science
Logic
Abstract
Wolfram [2, p. 707] and Cook [1, p. 3] claim to prove that a (2,5) Turing machine (2 states, 5 symbols) is universal, via a universal cellular automaton known as Rule 110. The first part of this paper points out a critical gap in their argument. The second part bridges the gap, thereby giving what appears to be the first proof of universality.
Cite
@article{arxiv.1208.6342,
title = {Is Wolfram and Cook's (2,5) Turing machine really universal?},
author = {Dominic J. D. Hughes},
journal= {arXiv preprint arXiv:1208.6342},
year = {2012}
}
Comments
13-page draft. Languished untouched since 2007. Seek co-author to dot 'i's and cross 't's. Email if interested