RT info:eu-repo/semantics/article T1 Square matrices with the inverse diagonal property A1 Furtado, Susana A1 Johnson, Charles R. A1 Marijuán, Carlos A1 Pisonero, Miriam K1 Diagonal entries K1 Inverse K1 M-matrix K1 Positive definite K1 Principal minors K1 Totally Positive K1 Triangular K1 Tridiagonal AB We identify the class of real square invertible matrices A for which the signs of the diagonal entries of A 1 match those of A, and begin their study. We say such matrices have the inverse diagonal property (IDP). This class includes many important classes: the positive definite matrices, the M-matrices, the totally positive matrices and some variants, the P-matrices, the diagonally dominant and H-matrices and their inverse classes, as well as triangular matrices. This class is closed under any real invertible diagonal multiplication on either the right or the left. So questions about this class can be reduced to the case of positive diagonal entries. Other basic properties are given. One theme is what conditions need be added to the IDP to insure membership in a familiar class. For example, the positive definite matrices are characterized as certain IDP matrices with special conditions on certain particular principal minors. The tridiagonal case is highlighted. Certain specially simple conditions on such matrices are mentioned that ensure them to be P-matrices, positive definite matrices or M-matrices. We also note that recent results about the invertibility of weakly diagonally dominant matrices are used. Examples are given throughout the paper. PB Elsevier SN 2307-4108 (Print) 2307-4116 (Online) YR 2023 FD 2023 LK https://uvadoc.uva.es/handle/10324/65405 UL https://uvadoc.uva.es/handle/10324/65405 LA eng NO Kuwait Journal of Science NO Producción Científica DS UVaDOC RD 08-ago-2024