We introduce completely symmetric D2L systems and cellular automata by means of an additional restriction on the corresponding symmetric devices. Then we show that completely symmetric D2L systems and cellular automata are still able to simulate Turing machine computations. As corollaries we obtain new characterizations of the recursively enumerable languages and of some space-bounded complexity classes.
- HMI-SLT: Speech and Language Technology
- D2L system
- Cellular automaton
- Recursively enumerable language (r.e.)
- Space-bounded complexity class