Kivunge, B.Ji Young ChoiLuz Maria DeAlbaLeslie HogbenSandra K. NordstromMike Shedenhelm2015-02-172015-02-172014Electronic Journal of Linear Algebra ISSN 1081-3810 A publication of the International Linear Algebra Society Volume 10, pp. 46-59, March 20031081-3810http://www.math.technion.ac.il/iic/ela/ela-articles/articles/vol10_pp46-59.pdfhttp://ir-library.ku.ac.ke/handle/123456789/12249In this paperthe nonnegative P0-matrix completion problem is considered. It is shown that a pattern for 4 × 4 matrices that includes all diagonal positions has nonnegative P0- completion if and only if its digraph is complete when it has a 4-cycle. It is also shown that any positionally symmetric pattern that includes all diagonal positions and whose graph is an n-cycle has nonnegative P0-completion if and only if n = 4.enMatrix completionP0-matrixNonnegative P0-matrixL-digraphn-cycleArticle