The basic matrix operations that we will deal with are addition and subtraction \begin{equation} \mathbf{A}= \mathbf{B}\pm\mathbf{C} \Longrightarrow a_{ij} = b_{ij}\pm c_{ij}, \tag{1} \end{equation} scalar-matrix multiplication \begin{equation} \mathbf{A}= \gamma\mathbf{B} \Longrightarrow a_{ij} = \gamma b_{ij}, \tag{2} \end{equation} vector-matrix multiplication