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Matematika 2006
Improvements on Geometric Means Related to the Tracy-Singh Products of Positive MatricesKeywords: Tracy-Singh product , Khatri-Rao product , Kronecker product , Hadamard product , Positive definite matrix , Geometric means , weighted geometric means. Abstract: In this paper, a family of geometric means for positive matrices is studied; we discuss possible definitions of the geometric means of positive matrices, and some counter examples are given. It is still an open problem to find a completely satisfactory definition. Other problems are how to define the geometric, arithmetic, harmonic, α power and operator means of finitely many positive matrices. We generalize these means of two positive matrices to arrive the definitions of the weighted means of k positive matrices. We recover and develop the relationship between the Ando’s geometric mean and the Kronecker product to the Tracy-Singh product and other means. Some new attractive inequalities for the Tracy-Singh product, Khatri-Rao product and geometric means of several positive matrices are established. The results lead to the case of Kronecker and Hadamard products of any finite numbers of matrices.
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