Let \(\alpha, \beta \in \mathbb{N}^n\) multi-indices. Then
\begin{equation*} \alpha\pm \beta=(\alpha_1\pm \beta_1,\ldots,\alpha_n\pm \beta_n). \end{equation*}Let \(\alpha, \beta \in \mathbb{N}^n\) multi-indices. Then
\begin{equation*} \alpha\pm \beta=(\alpha_1\pm \beta_1,\ldots,\alpha_n\pm \beta_n). \end{equation*}