  A manifestly Lorentz-covariant formulation of Loop Quantum Gravity (LQG) is
given in terms of finite-dimensional representations of the Lorentz group. The
formulation accounts for discrete symmetries, such as parity and time-reversal,
and it establishes a link with Wigner classification of particles. The
resulting quantum model can be seen as LQG with the internal $SU(2)\otimes
SU(2)$ group and it is free of the Immirzi parameter, while the scalar
constraint is just the Euclidean part.
