Block analogies of comparison matrices Original Research Article

A Hadamard-type comparison matrix H(A) is defined for block matrices A. With this notion, an extension to block matrices is given for Ostrowskiʹs inequality det A≥ det H(A). A related notion of equimodularity is introduced, and a block analogy of the result of Camion and Hoffman is porved: all matrices equimodular with a given A are nonsingular if and only if, after a permutation, H(A) is a (nonsingular) M-matrix.