We consider a transformation of a normalized measure space such that the image of any point is a finite set. We call such a transformation an m-transformation. In this case the orbit of any point looks like a tree. In the study of m-transformations we are interested in the properties of the trees. An m-transformation generates a stochastic kernel and a new measure. Using these objects, we introduce analogies of some main concept of ergodic theory: ergodicity, Koopman and Frobenius-Perron operators etc. We prove ergodic theorems and consider examples. We also indicate possible applications to fractal geometry and give a generalization of our construction.
DVI format ( 56 Kb), ZIP-ed DVI format ( 22 Kb),
ZIP-ed PostScript format ( 152 Kb), ZIP-ed PDF format (121 Kb )