About entropy

Document Type : Promotional Paper

Author

Faculty of Basic Sciences, Islamic Azad University, Dezful Branch, Dezful, Iran

Abstract

In irreducible subshifts, a word $m$ is synchronizing if whenever $vm$ and $mw$ are admissible words, then $vmw$ is admissible as well. A word $m$ is (left) half (resp. weak) synchronizing, when there is a left transitive ray (resp. a left ray) $x_-$ such that if $x_-m$ and $mw$ are admissible, then $x_-mw$ is also admissible. The resp ective subshifts are called half (resp. weak) synchronized. K. Thomsen considers a synchronized comp onent of a general subshift and investigates the approximation of entropy from inside of this comp onent by some certain SFTs. We, using a rather different approach, show how this result extends to weak synchronized systems.
 
The notion of balanced generator of the Dyke system has b een extended to a general subshift called balanced shift and it has b een shown that they are essentially mixing. All balanced shifts are half synchronized and full shifts are
the only balanced and synchronized subshifts. Also, a formula for the weak half synchronizing entropy of a balanced shift has b een given.

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Main Subjects


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Volume 6, Issue 4 - Serial Number 4
December 2021
Pages 7-27
  • Receive Date: 08 February 2022
  • Revise Date: 05 August 2022
  • Accept Date: 17 August 2022
  • Publish Date: 20 February 2022