The main results:
quantum mechanical problem of the electron moving in the Aharonov-Bom potential is formulated and solved as a problem of constructing the selfadjoint extension of the Hamiltonian; discovery of the global (BRST) supersymmetry of the effective action of quantum gauge theory; proof of gauge invariant renormalizability of a general gauge theory и independence of the beta-functions from gauge fixing (with B.Voronov); proof of the equivalence of the Lagrange and Hamilton quantizations of gauge theories (with I.Batalin and R.Grigoryan; a method of constructing the asimptotically free models is developed (with B.Voronov); the Sp(2)-covariant formulation of general gauge theory (with I.Batalin, P.Lavrov) and general covariant field-antifield formalism (with I.Batalin) are constructed; mathematical correct formalism in which the action of higher order variational local differential operators on local functionals does not contain indefinite quantities like delta(0) is developed (with B.Voronov and S.Shahverdiev); general forms of the *-products and *-commutators on the Grassman algebra are found.
Two monographies on quantization of the constraint systems:
D.M.Gitman, I.V.Tyutin. Canonical quantization of Fields with Constraints (in Russian), Наука, Москва, 1986, 216 p.;
D.M.Gitman, I.V.Tyutin. Quantization of Fields with Constraints, Springer-Verlag, 1990, 291 p.