About #36, I was thinking in representing the relation \$$G \subseteq S \times T\$$ as a function \$$\hat{g} :S \to \mathcal{P}(T)\$$ and adapt the definition of page 21, so \$$\forall s \in S, t \in T: s G t \iff t \in \hat{g}(s)\$$. Then define as there the partition in \$$T\$$ in terms of the relation \$$\sim\$$ given by \$$\forall t_1, t_2 \in T: t_1 \sim t_2 \iff \exists s_1, s_2 \in S\$$ such that \$$s_1 \sim s_2\$$ with \$$t_1 \in \hat{g}(s_1)\$$ and \$$t_2 \in \hat{g}(s_2)\$$, and forming its transitve closure.