The – matrix completion problem for digraphs of matrices with less than four directed lines

Abstract

A real matrix is said to be –matrix if its principal minors are nonnegative and all its non-diagonal entries are non-positive. In this project, we consider the –matrix completion problem. It is shown that any digraph with less than four directed lines which is not a cycle has –completion. It is further shown that digraph of matrix with less than four directed lines which is a cycle does not have –completion