Properties of G-Equivalence of Matrices

The theorem of Hilbert- Burch provides a description of codimension two determinantal varieties and their deformations in terms of their presentation matrices. In this work we use this correspondence to study properties of determinantal varieties, based on methods of singularity theory. We establish the theory of singularities for nxp matrices extending previous results of Bruce and Tari and Fr\"uhbis-Kr\"uger. The main result of this work is the description of equivalent conditions to G-finite determinacy of the presentation matrix of Cohen-Macaulay varieties of codimension 2. We apply the results to obtain sufficient conditions for topological triviality of deformations of weighted homogeneous matrices.