Non-Rigid Rank-One Infinite Measures on the Circle

TL;DR

This paper constructs and classifies non-rigid, infinite, ergodic measures for irrational rotations, revealing new examples of transformations with specific spectral properties and answering longstanding questions in ergodic theory.

Contribution

It introduces explicit rank-one transformations with infinite measures for irrational rotations, classifies their finiteness, and provides new examples of non-weakly mixing ergodic transformations.

Findings

Constructed explicit rank-one transformations for certain irrational numbers.

Classified when measures are finite or infinite, linking to irrational rotations.

Provided examples of non-weakly mixing ergodic transformations without nontrivial discrete spectrum factors.

Abstract

For a class of irrational numbers, depending on their Diophantine properties, we construct explicit rank-one transformations that are totally ergodic and not weakly mixing. We classify when the measure is finite or infinite. In the finite case they are isomorphic to irrational rotations. We also obtain rank-one nonrigid infinite invariant measures for irrational rotations, and, for each Krieger type, nonsingular measures on irrational rotations. In the third version, in the infinite case we use the constructions to provide examples of non-weakly mixing infinite measure-preserving ergodic transformations which do not have any nontrivial probability preserving factors with discrete spectrum, thereby answering a questions of Aaronson and Nakada and of Glasner and Weiss.