This paper proposes a standard for notation in econometrics. It presents a fully integrated and internally consistent framework for notation and abbreviations, which is as close as possible to existing common practice. The symbols used are instantly recognizable and interpretable, thus...

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.