Automata and Square Complexes
Group Theory
2007-05-23 v1
Abstract
We introduce a new geometric tool for analyzing groups of finite automata. To each finite automaton we associate a square complex. The square complex is covered by a product of two trees iff the automaton is bi-reversible. Using this method we give examples of free groups and of Kazhdan groups which are generated by the different states of one finite (bi-reversible) automaton. We also reproduce the theorem of Macedonska, Nekrashevych, Sushchansky, on the connection between bi-reversible automata and the commensurator of a regular tree.
Cite
@article{arxiv.math/0306259,
title = {Automata and Square Complexes},
author = {Yair Glasner and Shahar Mozes},
journal= {arXiv preprint arXiv:math/0306259},
year = {2007}
}
Comments
21 pages, 4 figures