The theory of difference equations is now enjoying a period of
Renaissance. Witness the large number of papers in which problems,
having at first sight no common features, are reduced to the
investigation of subsequent iterations of the maps f- IR. m IR. m, m >
0, or (which is, in fact, the same) to difference equations The world of
difference equations, which has been almost hidden up to now, begins to
open in all its richness. Those experts, who usually use differential
equations and, in fact, believe in their universality, are now
discovering a completely new approach which re- sembles the theory of
ordinary differential equations only slightly. Difference equations,
which reflect one of the essential properties of the real world-its
discreteness-rightful- ly occupy a worthy place in mathematics and its
applications. The aim of the present book is to acquaint the reader with
some recently discovered and (at first sight) unusual properties of
solutions for nonlinear difference equations. These properties enable us
to use difference equations in order to model complicated os- cillating
processes (this can often be done in those cases when it is difficult to
apply ordinary differential equations). Difference equations are also a
useful tool of syn- ergetics- an emerging science concerned with the
study of ordered structures. The application of these equations opens up
new approaches in solving one of the central problems of modern
science-the problem of turbulence.