In this paper we introduce and study new notions of uniform recurrence in multidimensional words. A d-dimensional word is called uniformly recurrent if for all (s1,…,sd)∈Nd there exists n∈N such that each block of size (n,…,n) contains the prefix of size (s1,…,sd). We are interested in a modification of this property. Namely, we ask that for each rational direction (q1,…,qd), each rectangular prefix occurs along this direction in positions ℓ(q1,…,qd) with bounded gaps. Such words are called uniformly recurrent along all directions. We provide several constructions of multidimensional words satisfying this condition, and more generally, a series of four increasingly stronger conditions. In particular, we study the uniform recurrence along directions of multidimensional rotation words and of fixed points of square morphisms.

Original languageEnglish
Article number112006
Number of pages23
JournalDiscrete Mathematics
Volume343
Issue number10
DOIs
StatePublished - Oct 2020

    Scopus subject areas

  • Theoretical Computer Science
  • Discrete Mathematics and Combinatorics

    Research areas

  • Multidimensional morphisms, Multidimensional words, Uniform recurrence, SEQUENCES, TILINGS, COMBINATORICS

ID: 62340716