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Set-theoretical entropies of weighted generalized shifts

General Mathematics 2024-10-30 v3

Abstract

In this paper for a finite field FF, a nonempty set Γ\Gamma, a self--map φ:ΓΓ\varphi:\Gamma\to\Gamma and a weight vector wFΓ\mathfrak{w}\in F^\Gamma, we show that the set--theoretical entropy of the weighted generalized shift σφ,w:FΓFΓ\sigma_{\varphi,\mathfrak{w}}:F^\Gamma\to F^\Gamma is either zero or ++\infty, moreover it is equal to zero if and only if σφ,w\sigma_{\varphi,\mathfrak{w}} is quasi--periodic. On the other hand after characterizing all conditions under which σφ,w:FΓFΓ\sigma_{\varphi,\mathfrak{w}}:F^\Gamma\to F^\Gamma is of finite fibre, we show that the contravariant set--theoretical entropy of a finite fibre σφ,w:FΓFΓ\sigma_{\varphi,\mathfrak{w}}:F^\Gamma\to F^\Gamma depends only on φ\varphi and supp(w)\rm{supp}(\mathfrak{w}). In final sections we study the restriction of σφ,w\sigma_{\varphi,\mathfrak{w}} to the direct sum ΓF\mathop{\bigoplus}\limits_{\Gamma}F.

Keywords

Cite

@article{arxiv.2206.09118,
  title  = {Set-theoretical entropies of weighted generalized shifts},
  author = {Fatemah Ayatollah Zadeh Shirazi and Arezoo Hosseini and Lida Mousavi and Reza Rezavand},
  journal= {arXiv preprint arXiv:2206.09118},
  year   = {2024}
}

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28 pages