TY - JOUR T1 - The totally non-positive matrix completion problem AU - J. P. Liang & M. He JO - Numerical Mathematics, a Journal of Chinese Universities VL - 4 SP - 312 EP - 319 PY - 2006 DA - 2006/11 SN - 15 DO - http://doi.org/ UR - https://global-sci.org/intro/article_detail/nm/8039.html KW - AB - In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has, in general, a negative answer. Therefore, our question is for what kind of labeled graphs $G$ each partial totally non-positive matrix whose associated graph is $G$ has a totally non-positive completion? If $G$ is not a monotonically labeled graph or monotonically labeled cycle, we give necessary and sufficient conditions that guarantee the existence of the desired completion.