  We derive novel explicit formulas for the inverses of truncated block
Toeplitz matrices that correspond to a multivariate minimal stationary process.
The main ingredients of the formulas are the Fourier coefficients of the phase
function attached to the spectral density of the process. The derivation of the
formulas is based on a recently developed finite prediction theory applied to
the dual process of the stationary process. We illustrate the usefulness of the
formulas by two applications. The first one is a strong convergence result for
solutions of general block Toeplitz systems for a multivariate short-memory
process. The second application is closed-form formulas for the inverses of
truncated block Toeplitz matrices corresponding to a multivariate ARMA process.
The significance of the latter is that they provide us with a linear-time
algorithm to compute the solutions of corresponding block Toeplitz systems.
