English

Almost full entropy subshifts uncorrelated to the M\"obius function

Dynamical Systems 2016-11-08 v1

Abstract

We show that if y=(yn)n1y=(y_n)_{n\ge 1} is a bounded sequence with zero average along every infinite arithmetic progression then for every N2N\ge 2 there exist (unilateral or bilateral) subshifts Σ\Sigma over NN symbols, with entropy arbitrarily close to logN\log N, uncorrelated to yy. In particular, for y=μy=\mu being the M\"obius function, we get that there exist subshifts as above which satisfy the assertion of Sarnak's conjecture. The existence of positive entropy systems uncorrelated to the M\"obius function is claimed in Sarnak's survey \cite{sarnak} (and attributed to Bourgain), however, to our knowledge no examples have ever been published. We fill in this gap and by the way we show that this has nothing to do with more advanced algebraic properties (for instance multiplicativity) of the considered sequence.

Keywords

Cite

@article{arxiv.1611.02084,
  title  = {Almost full entropy subshifts uncorrelated to the M\"obius function},
  author = {Tomasz Downarowicz and Jacek Serafin},
  journal= {arXiv preprint arXiv:1611.02084},
  year   = {2016}
}

Comments

10 pages

R2 v1 2026-06-22T16:44:17.360Z