New statements of problems arose recently demanding thorough ana- lysis.
Notice, first of all, the statements of problems using adjoint equations
which gradually became part of our life. Adjoint equations are capable
to bring fresh ideas to various problems of new technology based on
linear and nonlinear processes. They became part of golden fund of
science through quantum mechanics, theory of nuclear reactors, optimal
control, and finally helped in solving many problems on the basis of
perturbation method and sensitivity theory. To emphasize the important
role of adjoint problems in science one should mention four-dimensional
analysis problem and solution of inverse problems. This range of
problems includes first of all problems of global climate changes on our
planet, state of environment and protection of environ- ment against
pollution, preservation of the biosphere in conditions of vigorous
growth of population, intensive development of industry, and many
others. All this required complex study of large systems: interac- tion
between the atmosphere and oceans and continents in the theory of
climate, cenoses in the biosphere affected by pollution of natural and
anthropogenic origin. Problems of local and global perturbations and
models sensitivity to input data join into common complex system.