Equivalencies between beta-shifts and S-gap shifts

TL;DR

This paper explores the relationships between beta-shifts and S-gap shifts, establishing conditions for their equivalence, conjugacy, and almost conjugacy, especially focusing on sofic and non-sofic cases.

Contribution

It characterizes when beta-shifts and S-gap shifts are (almost) conjugate or equivalent, providing new insights into their structural relationships and limitations.

Findings

Sofic beta-shifts are almost conjugate to certain S-gap shifts.

Conjugacy exists between SFT beta-shifts and S-gap shifts.

Non-SFT beta-shifts are not conjugate to any S-gap shift.

Abstract

Let $ X_{\beta}$ be a sofic $ \beta $-shift for $ \beta \in (1, 2] $. We show that there is an $ S $-gap shift $ X(S) $ such that $ X_{\beta} $ and $ X(S) $ are right-resolving almost conjugate. Conversely, a condition on $ S \subseteq \mathbb N\cup \{0\} $ is given such that for this $S$, there is a $ \beta $ such that $ X(S) $ and $ X_{\beta} $ have the same equivalency. We show that if $X_\beta$ is SFT, then there is an $S$-gap shift conjugate to this $X_\beta$; however, if $X_\beta$ is not SFT, then no $S$-gap shift is conjugate to $X_\beta$. Also we will investigate the existence of these sort of equivalencies for non-sofics.