The simplified derivation of the completion theorem to a unimodular matrix over R[zl, z2]

As indicated in a previous paper, there is a need for a simple constructive proof of the completion theorem of a 2-D unimodular matrix. The proof provided here is based on the concept of coprimeness of 2-D polynomial matrices and the 2-D version of the matrix fraction description (MFD) of a 2-D transfer function matrix as investigated by Morf et al. [6] and Youla and Gnavi [5].