Total gluon propagator in the light-cone gauge and the problem of the transversality of the polarization operator in the infrared region. I

The tensor structure of the gluon polarization operator is investigated in the lightlike gauge on the basis of the Dyson–Schwinger equation completed by the Slavnov–Taylor identities. The most general form of the gluon propagator is obtained that satisfies the contracted Dyson–Schwinger equation in the infrared region. Two-loop terms of the polarization operator are studied as well in the case when only one tensor structure is retained in the gluon propagator and the leading singular behaviour is taken into account. It is shown that the polarization operator is nonsymmetrical in this approximation.