  We present a novel implementation of the Schwinger mechanism in QCD, which
fixes uniquely the scale of the effective gluon mass and streamlines
considerably the procedure of multiplicative renormalization. The key advantage
of this method stems from the nonlinear nature of the dynamical equation that
generates massless poles in the longitudinal sector of the three-gluon vertex.
An exceptional feature of this approach is an extensive cancellation involving
the components of the integral expression that determines the gluon mass; it is
triggered once the Schwinger-Dyson equation of the pole-free part of the
three-gluon vertex has been appropriately exploited. It turns out that this
cancellation is driven by the so-called Fredholm alternatives theorem, which
operates among the set of integral equations describing this system. Quite
remarkably, in the linearized approximation this theorem enforces the exact
masslessness of the gluon. Instead, the nonlinearity induced by the full
treatment of the relevant kernel evades this theorem, allowing for the
emergence of a nonvanishing mass. The numerical results obtained from the
resulting equations are compatible with the lattice findings, and may be
further refined through the inclusion of the remaining fundamental vertices of
the theory.
