The Role of Translational Invariance in Nonlinear Gauge Theories of Gravity

The internal structure of the tetrads in a Poincaré non linear gauge theory of gravity is considered. Minkowskian coordinates becomes dynamical degrees of freedom playing the role of Goldstone bosons of the translations. A critical length allowing a covariant expansion similar to the weak field approach is deduced, the zeroth order metric being maximally symmetric (Minkowskian in some cases).