## Abstract

A square matrix *A* over the field of complex numbers is said to be Hermitian if \(A = A^{*}\), the conjugate transpose of *A*, while Hermitian matrices are known to be an important class of matrices. In addition to the definition, a Hermitian matrix can be characterized by some other matrix equalities. This fact can be described in the implication form \(f(A, A^{*}) = 0 \Leftrightarrow A = A^{*}\), where \(f(\cdot )\) denotes certain ordinary algebraic operation of *A* and \(A^{*}\). In this note, we show two special cases of the equivalent facts: \(AA^{*}A = A^{*}AA^{*} \Leftrightarrow A^3 = AA^{*}A \Leftrightarrow A = A^{*}\) without assuming the invertibility of *A* through the skillful use of decompositions and determinants of matrices. Several consequences and extensions are presented to a selection of matrix equalities composed of multiple products of *A* and \(A^{*}\).

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Tian, Y. Some New Characterizations of a Hermitian Matrix and Their Applications.
*Complex Anal. Oper. Theory* **18**, 2 (2024). https://doi.org/10.1007/s11785-023-01440-x

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DOI: https://doi.org/10.1007/s11785-023-01440-x