This is possibly a stupid question. But in question 3b of exercise 3, we are supposed to show that $R(T) \cup \set{r}$ is not consistent for alll $r = (xy|z) \notin R(T)$.
Are the $x,y,z$ in the triple $r$ restricted to come from the same leaf-set $L$? Or can $R(T) \cup \set{r}$ be over leafset $L \cup \set{x,y,z}$?