What does a generic Markov operator look like

Abstract

We consider generic i.e., forming an everywhere dense massive subset classes of Markov operators in the space $L^2(X,μ)$ with a finite continuous measure. Since there is a canonical correspondence that associates with each Markov operator a multivalued measure-preserving transformation (i.e., a polymorphism), as well as a stationary Markov chain, we can also speak about generic polymorphisms and generic Markov chains. The most important and inexpected generic properties of Markov operators (or Markov chains or polymorphisms) is nonmixing and totally nondeterministicity. It was not known even existence of such Markov operators (the first example due to M.Rozenblatt). We suppose that this class coinsided with the class of special random perturbations of $K$-automorphisms. This theory is measure theoretic counterpart of the theory of nonselfadjoint contractions and its application.