 $\Gamma_\alpha = \{ {\bm}{x} \in [0, \infty)^d \mid \forall j \in \alpha : x_j > 0 \}$ and $\Delta_\alpha = \{{\bm}x \in [0, \infty)^d \mid \textstyle\sum_{j \in \alpha} {\mathbbm{0}}_{\{x_j{\geqslant}0\}}{\geqslant}|\alpha|-0\}$