ArticleOriginal scientific textInfinite ergodic index
Title
Infinite ergodic index -actions in infinite measure
Authors 1, 2, 3, 4, 3,
Affiliations
- Lexecon Inc., One Mifflin Place, Cambridge, MA 02138, U.S.A.
- 480 Lincoln Drive, Department of Mathematics, University of Wisconsin, Madison, Madison, WI 53706, U.S.A.
- Department of Mathematics, Williams College, Williamstown, MA 01267, U.S.A.
- 1750 41st Avenue, San Francisco, CA 94122, U.S.A.
- Department of Mathematics, Cornell University, Malott Hall, Ithaca, NY 14853, U.S.A.
Abstract
We construct infinite measure preserving and nonsingular rank one -actions. The first example is ergodic infinite measure preserving but with nonergodic, infinite conservative index, basis transformations; in this case we exhibit sets of increasing finite and infinite measure which are properly exhaustive and weakly wandering. The next examples are staircase rank one infinite measure preserving -actions; for these we show that the individual basis transformations have conservative ergodic Cartesian products of all orders, hence infinite ergodic index. We generalize this example to obtain a stronger condition called power weakly mixing. The last examples are nonsingular -actions for each Krieger ratio set type with individual basis transformations with similar properties.
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