CIRJE-F-476. Magnus, Jan R. and Karim M. Abadir, "On some definitions in matrix algebra", February 2007.

Many definitions in matrix algebra are not standardized. This notediscusses some of thepitfalls associated with undesirable orwrong definitions, anddealswith central conceptslikesymmetry, orthogonality, square root, Hermitian and quadratic forms, and matrix derivatives.