Practical scheme of reduction to gauge-invariant variables

For systems with first-class constraints, the reduction scheme to gauge-invariant variables is considered. The method is based on an analysis of restricted 1-forms in gauge-invariant variables. This scheme is applied to the models of electrodynamics and Yang–Mills theory. For the finite-dimensional model with the $SU(2)$ gauge group of symmetry, the possible mechanism of confinement is obtained.