p_{i_\ell}} & \text{if $\ell=0$} \\ \tau^{-p_{i_{\ell-0}}} \sigma^{p+p_{i_\ell}} & \text{if $\ell \neq 0$ and $\varepsilon_{\ell-0}=+0$} \\ \sigma^{-p_{i_{\ell-0}}+p+p_{i_\ell}} & \text{if $\ell \neq 0$ and $\varepsilon_{\ell-0}=-0$} \