Transitive actions and purely periodic N-expansions.

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Bibliographic Details
Title: Transitive actions and purely periodic N-expansions.
Authors: Javaheri, Mohammad1 (AUTHOR) mjavaheri@siena.edu
Source: Journal of Number Theory. Jun2026, Vol. 283, p1-14. 14p.
Subjects: Semigroups (Algebra), Rational numbers, Dynamical systems, System dynamics
Abstract: We study the dynamical properties of the semigroup 〈 f , g 〉 generated by the maps f (x) = x + 1 and g (x) = N / x acting on the positive rational numbers Q + , with a focus on their connection to N -expansions. For N ∈ N ∖ { 1 , 2 , 3 , 4 , 6 } , we establish the existence of an infinite subset A ⊆ Q + on which 〈 f , g 〉 acts transitively: for any x , y ∈ A , there exists σ ∈ 〈 f , g 〉 such that y = σ (x). We use this result to show that, for the same values of N , there are infinitely many rational numbers with purely periodic N -expansions of any sufficiently large minimal period. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:We study the dynamical properties of the semigroup 〈 f , g 〉 generated by the maps f (x) = x + 1 and g (x) = N / x acting on the positive rational numbers Q + , with a focus on their connection to N -expansions. For N ∈ N ∖ { 1 , 2 , 3 , 4 , 6 } , we establish the existence of an infinite subset A ⊆ Q + on which 〈 f , g 〉 acts transitively: for any x , y ∈ A , there exists σ ∈ 〈 f , g 〉 such that y = σ (x). We use this result to show that, for the same values of N , there are infinitely many rational numbers with purely periodic N -expansions of any sufficiently large minimal period. [ABSTRACT FROM AUTHOR]
ISSN:0022314X
DOI:10.1016/j.jnt.2025.11.013