{ "id": "2011.14278", "version": "v1", "published": "2020-11-29T04:35:17.000Z", "updated": "2020-11-29T04:35:17.000Z", "title": "Nonsingular transformations that are ergodic with isometric coefficients and not weakly doubly ergodic", "authors": [ "James Leng", "Cesar E. Silva" ], "categories": [ "math.DS" ], "abstract": "We study two properties of nonsingular and infinite measure-preserving ergodic systems: weak double ergodicity, and ergodicity with isometric coefficients. We show that there exist infinite measure-preserving transformations that are ergodic with isometric coefficients but are not weakly doubly ergodic. We also give type $\\text{III}_\\lambda$ examples of such systems, $0<\\lambda\\leq 1$. We prove that under certain hypotheses, systems that are weakly mixing are ergodic with isometric coefficients and along the way we give an example of a uniformly rigid topological dynamical system along the sequence $(n_i)$ that is not measure theoretically rigid along $(n_i)$ for any nonsingular ergodic finite measure.", "revisions": [ { "version": "v1", "updated": "2020-11-29T04:35:17.000Z" } ], "analyses": { "subjects": [ "37A40", "37A05", "37A50", "37A05", "37A50", "37A50" ], "keywords": [ "isometric coefficients", "weakly doubly ergodic", "nonsingular transformations", "rigid topological dynamical system", "nonsingular ergodic finite measure" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }