Mathematical methods have been applied successfully to population genet-
ics for a long time. Even the quite elementary ideas used initially
proved amazingly effective. For example, the famous Hardy-Weinberg Law
(1908) is basic to many calculations in population genetics. The
mathematics in the classical works of Fisher, Haldane and Wright was
also not very complicated but was of great help for the theoretical
understanding of evolutionary pro- cesses. More recently, the methods of
mathematical genetics have become more sophisticated. In use are
probability theory, stochastic processes, non- linear differential and
difference equations and nonassociative algebras. First contacts with
topology have been established. Now in addition to the tra- ditional
movement of mathematics for genetics, inspiration is flowing in the
opposite direction, yielding mathematics from genetics. The present
mono- grapll reflects to some degree both patterns but especially the
latter one. A pioneer of this synthesis was S. N. Bernstein. He
raised-and partially solved- -the problem of characterizing all
stationary evolutionary operators, and this work was continued by the
author in a series of papers (1971-1979). This problem has not been
completely solved, but it appears that only cer- tain operators devoid
of any biological significance remain to be addressed. The results of
these studies appear in chapters 4 and 5. The necessary alge- braic
preliminaries are described in chapter 3 after some elementary models in
chapter 2.