Practical criteria for positive-definite matrix, M-matrix and Hurwitz matrix

All the conventional criterions to verify if a matrix is positive definite, Hurwitz or an M-matrix, such as Sylvester condition and Hurwitz theorem, require us to compute n determinants. This paper develops a new and simple criterion, based on a new type of Gaussian elimination process. In contrast to the traditional criterions, the new criterion only computes one determinate. Thus, the computing cost is greatly reduced. An illustrative example is given to show the application of the new criterion in the stability analysis of Hopfied-type neural networks with time delays.