English

Forbidden substrings, Kolmogorov complexity and almost periodic sequences

Combinatorics 2010-09-28 v1 Discrete Mathematics

Abstract

Assume that for some α<1\alpha<1 and for all nutural nn a set FnF_n of at most 2αn2^{\alpha n} "forbidden" binary strings of length nn is fixed. Then there exists an infinite binary sequence ω\omega that does not have (long) forbidden substrings. We prove this combinatorial statement by translating it into a statement about Kolmogorov complexity and compare this proof with a combinatorial one based on Laslo Lovasz local lemma. Then we construct an almost periodic sequence with the same property (thus combines the results of Levin and Muchnik-Semenov-Ushakov). Both the combinatorial proof and Kolmogorov complexity argument can be generalized to the multidimensional case.

Keywords

Cite

@article{arxiv.1009.4455,
  title  = {Forbidden substrings, Kolmogorov complexity and almost periodic sequences},
  author = {Andrey Rumyantsev and Maxim Ushakov},
  journal= {arXiv preprint arXiv:1009.4455},
  year   = {2010}
}
R2 v1 2026-06-21T16:17:47.193Z