Probabilistic methods can be applied very successfully to a number of
asymptotic problems for second-order linear and non-linear partial
differential equations. Due to the close connection between the second
order differential operators with a non-negative characteristic form on
the one hand and Markov processes on the other, many problems in PDE's
can be reformulated as problems for corresponding stochastic processes
and vice versa. In the present book four classes of problems are
considered: - the Dirichlet problem with a small parameter in higher
derivatives for differential equations and systems - the averaging
principle for stochastic processes and PDE's - homogenization in PDE's
and in stochastic processes - wave front propagation for semilinear
differential equations and systems. From the probabilistic point of
view, the first two topics concern random perturbations of dynamical
systems. The third topic, homog- enization, is a natural problem for
stochastic processes as well as for PDE's. Wave fronts in semilinear
PDE's are interesting examples of pattern formation in
reaction-diffusion equations. The text presents new results in
probability theory and their applica- tion to the above problems.
Various examples help the reader to understand the effects.
Prerequisites are knowledge in probability theory and in partial
differential equations.