## M-Tensors and Nonsingular M-Tensors

报告题目： M-Tensors and Nonsingular M-Tensors

报告人: 魏益民 教授（复旦大学数学学院）

时间：2013年11月1日（星期五）16:00-17:00

地点：理科楼数学系A404

摘要: The M-matrix is an important concept in matrix theory, and has many applications. Recently, this concept has been extended to higher order tensors. In this paper, we establish some important properties of M-tensors and nonsingular M-tensors. An M-tensor is a Z-tensor. We show that a Z-tensor is a nonsingular M-tensor if and only if it is semi-positive. Thus, a nonsingular M-tensor has all positive diagonal entries; and an M-tensor, regarding as the limitation of a series of nonsingular M-tensors, has all nonnegative diagonal entries. We introduce even-order monotone tensors and present their spectral properties. In matrix theory, a Z-matrix is a nonsingular M-matrix if and only if it is monotone. This is no longer true in the case of higher order tensors. We show that an even-order monotone Z-tensor is an even-order nonsingular M-tensor but not vice versa. An example of an even-order nontrivial monotone Z-tensor is also given.

联系人：贾仲孝