It is proved that the solutions of Tikhonov systems, in addition to having the property of a limiting transition, are pseudoholomorphic under certain conditions additional to the conditions of A.N. Tikhonov’s theorem. At the same time, the number of fast and slow variables can be anything. Both initial and boundary value problems for systems of this type are considered.

Introduced by S.A. Lomov, the concept of a pseudoanalytic (pseudoholomorphic) solution laid the foundation for the development of the singular perturbation analytical theory. In order for this concept to work in case of linear problems, an apparatus for the theory of exponential type vector spaces was developed. When considering nonlinear singularly perturbed problems, an algebraic approach is currently used. This approval is based on the properties of algebra homomorphisms for holomorphic functions with various numbers of variables, as a result of which it is possible to obtain pseudoholomorphic solutions. In this paper, formally singularly perturbed equations are considered in topological algebras, which allows the authors to formulate the main concepts of the singular perturbation analytical theory from the standpoint of maximal generality.