Definition:Ordered Sum/Informal Interpretation

Definition
We can consider the ordered sum $\struct {S \cup T, \preceq}$ as:


 * First the whole of $S$, ordered by $\preceq_1$
 * After that, the set $T \setminus S$, ordered by $\preceq_2$, where $T \setminus S$ denotes set difference.