Description
We perform a 3+1 decomposition in a general symmetric metric-affine theory, classifying the extrinsic tensors and deriving the generalized Gauss-Codazzi relations. The latter are exploited to perform the teleparallel limit in a model-independent fashion, thus identifying the extrinsic non-metricity tensor which plays the role of the extrinsic Riemannian curvature. We further prove that no other tensor field can induce new dynamical degrees of freedom. Moreover, by analyzing the Cauchy problem of STEGR we obtain constraints on the boundary terms and we conclude by building the Hamiltonian and performing the Hamiltonian analysis.