English

On the expressive power of quasiperiodic SFT

Discrete Mathematics 2017-06-27 v2

Abstract

In this paper we study the shifts, which are the shift-invariant and topologically closed sets of configurations over a finite alphabet in Zd\mathbb{Z}^d. The minimal shifts are those shifts in which all configurations contain exactly the same patterns. Two classes of shifts play a prominent role in symbolic dynamics, in language theory and in the theory of computability: the shifts of finite type (obtained by forbidding a finite number of finite patterns) and the effective shifts (obtained by forbidding a computably enumerable set of finite patterns). We prove that every effective minimal shift can be represented as a factor of a projective subdynamics on a minimal shift of finite type in a bigger (by 11) dimension. This result transfers to the class of minimal shifts a theorem by M.Hochman known for the class of all effective shifts and thus answers an open question by E.Jeandel. We prove a similar result for quasiperiodic shifts and also show that there exists a quasiperiodic shift of finite type for which Kolmogorov complexity of all patterns of size n×nn\times n is Ω(n)\Omega(n).

Keywords

Cite

@article{arxiv.1705.01876,
  title  = {On the expressive power of quasiperiodic SFT},
  author = {Bruno Durand and Andrei Romashchenko},
  journal= {arXiv preprint arXiv:1705.01876},
  year   = {2017}
}

Comments

22 pages, 8 figures. An extended version of a paper accepted for publication in the proceedings of MFCS 2017