$k$-Sum Decomposition of Strongly Unimodular Matrices
  Networks are frequently studied algebraically through matrices. In this work, we show that networks may be studied in a more abstract level using results from the theory of matroids by establishing connections to networks by decomposition results of matroids. First, we present the implications of the decomposition of regular matroids to networks and related classes of matrices, and secondly we show that strongly unimodular matrices are closed under $k$-sums for $k=1,2$ implying a decomposition into highly connected network-representing blocks, which are also shown to have a special structure. 
Konstantinos Papalamprou and Leonidas Pitsoulis
math.CO