Ergodic theory of dynamical systems i.e., the qualitative analysis of
iterations of a single transformation is nowadays a well developed
theory. In 1945 S. Ulam and J. von Neumann in their short note [44]
suggested to study ergodic theorems for the more general situation when
one applies in turn different transforma- tions chosen at random. Their
program was fulfilled by S. Kakutani [23] in 1951. 'Both papers
considered the case of transformations with a common invariant measure.
Recently Ohno [38] noticed that this condition was excessive. Ergodic
theorems are just the beginning of ergodic theory. Among further major
developments are the notions of entropy and characteristic exponents.
The purpose of this book is the study of the variety of ergodic
theoretical properties of evolution processes generated by independent
applications of transformations chosen at random from a certain class
according to some probability distribution. The book exhibits the first
systematic treatment of ergodic theory of random transformations i.e.,
an analysis of composed actions of independent random maps. This set up
allows a unified approach to many problems of dynamical systems,
products of random matrices and stochastic flows generated by stochastic
differential equations.