Modern achievements in the intensively developing field of applied mathematics as applied to physical chemistry are presented in this monograph. In particular, the monograph proposes a new approach to extremal problem theory for nonlinear operators, differential-operator equations and inclusions and for variational inequalities in Banach spaces. An axiomatic study of nonlinear maps (including multi-valued ones) is given, and the properties of resolving operators for systems, consisting of operator and differential-operator equations are stated in nonlinear-map terms. The solvability...