In [10] we introduced a new notion of isomorphisms for topological measure spaces, which preserve almost sure continuity of mappings, almost sure convergence of random variables, and weak convergence of probability measures. The main thrust of that paper is the construction of an isomorphism from a Polish space with a nonatomic Borel probability measure to the unit Lebesgue interval (I, *). App...

We prove that the isomorphism relation for separable C∗-algebras, and also the relations of complete and n-isometry for operator spaces and systems, are Borel reducible to the orbit equivalence relation of a Polish group action on a standard Borel space.

Let G be a closed subgroup of S∞ and X be a Polish G-space with a countable basisA of clopen sets. Each x ∈ X defines a characteristic function τx on A by τx(A) = 1 ⇔ x ∈ A. We consider computable complexity of τx and some related questions.

Given a Polish space X , a countable Borel equivalence relation E on X , and a Borel cocycle ρ : E → (0,∞), we characterize the circumstances under which there is a probability measure μ on X such that ρ(φ−1(x), x) = [d(φ∗μ)/dμ](x) μ-almost everywhere, for every Borel injection φ whose graph is contained in E.

We show that under some conditions on a family A ⊂ I there exists a subfamily A0 ⊂ A such that ⋃ A0 is nonmeasurable with respect to a fixed ideal I with Borel base of a fixed uncountable Polish space. Our result applies to the classical ideal of null subsets of the real line and to the ideal of first category subsets of the real line.

We show that the Baire measurable chromatic number of every locally finite Borel graph on a non-empty Polish space is strictly less than twice its ordinary chromatic number, provided this ordinary chromatic number is finite. In the special case that the connectedness equivalence relation is hyperfinite, we obtain the analogous result for the μ-measurable chromatic number.

For an exchangeable sequence of random variables ðX nÞn2N taking values in a Polish space, we obtain a necessary and sufficient condition for the large deviation principles with respect to the t-topology of the occupation measure Ln:1⁄4ð1=nÞ Pn 1 k1⁄40 dX k and of the process-level empirical measures. r 2006 Elsevier B.V. All rights reserved.

A renewal theorem is obtained for stationary sequences of the form ~,=~( . . . , Xn_ ~, X,, X,+I , ...), where X,, n~Z, are i.i.d.r.v.s, valued in a Polish space. This class of processes is sufficiently broad to encompass functionals of recurrent Markov chains, functionals of stationary Gaussian processes, and functionals of one-dimensional Gibbs states. The theorem is proved by a new coupling ...

We investigate the category of Eilenberg-Moore algebras for the Giry monad associated with stochastic relations over Polish spaces with continuous maps as morphisms. The algebras are characterized through convex partitions of the space of all probability measures. Examples are investigated, and it is shown that finite spaces usually do not have algebras at all.

For every Polish space and a coanalytic set of its countable subsets, if there is a homogeneous set of outer measure one then there is a perfect homogeneous set. In the generic extension by a large measure algebra, if there is a homogeneous set of size continuum then there is a a perfect homogeneous set.