The Classification of Some Order Four Digraphs As Nonnegative P0,1-Matrix Completion

Abstract

A digraph of order n is said to have nonnegative 0,1 P -completion if every partial nonnegative 0,1 P -matrix that specifies the digraph can be completed to a nonnegative 0,1 P - matrix. The aim of this paper is to classify some digraphs of order four that include all loops as either having nonnegative 0,1 P -completion or not having nonnegative 0,1 P - completion.