Four Small Universal Turing Machines
Fundamenta Informaticae - Machines, Computations and Universality, Part I
Small weakly universal turing machines
FCT'09 Proceedings of the 17th international conference on Fundamentals of computation theory
A universal cellular automaton on the heptagrid of the hyperbolic plane with four states
Theoretical Computer Science
Abstract geometrical computation 4: Small Turing universal signal machines
Theoretical Computer Science
On the complex behavior of simple tag systems-An experimental approach
Theoretical Computer Science
A new weakly universal cellular automaton in the 3D hyperbolic space with two states
RP'11 Proceedings of the 5th international conference on Reachability problems
The complexity of small universal turing machines: a survey
SOFSEM'12 Proceedings of the 38th international conference on Current Trends in Theory and Practice of Computer Science
Four Small Universal Turing Machines
Fundamenta Informaticae - Machines, Computations and Universality, Part I
Ten years of weakly universal cellular automata in the hyperbolic plane
ICCCI'12 Proceedings of the 4th international conference on Computational Collective Intelligence: technologies and applications - Volume Part I
Hi-index | 0.00 |
We present three small universal Turing machines that have 3 states and 7 symbols, 4 states and 5 symbols, and 2 states and 13 symbols, respectively. These machines are semi-weakly universal which means that on one side of the input they have an infinitely repeated word, and on the other side there is the usual infinitely repeated blank symbol. This work can be regarded as a continuation of early work by Watanabe on semi-weak machines. One of our machines has only 17 transition rules, making it the smallest known semi-weakly universal Turing machine. Interestingly, two of our machines are symmetric with Watanabe's 7-state and 3-symbol, and 5-state and 4-symbol machines, even though we use a different simulation technique.