The role of unimodular (E), paramount (M) and dominant matrices in network theory is described. A distinction is made between the unimodular matrices which represent the transformations of the current coordinates and those represent. ing the voltage coordinates of a network. A similar distinction can be made between the cut-set to branch and the loop to branch incidence matrices for adequate systems of node-pair voltages and link currents, respectively. Some new results concerning the synthesis of-a resistive

-port from its admittance or impedance matrix are given.