Exercises 10.2 and 10.5 are the hardest. So, also consider the other problems even if these first two problems cause you some difficulties. In 10.2, you do not need to build a priority search tree which looks exactly like the structure build using the normal construction method. You should just build something with the same asymptotic properties.
Origin of the problem (not relevant for solving it): The problem comes from query optimization in streaming databases. Streams are at the leaves of the evaluation tree and predicates may compare elements in different streams. Predicates must be evaluated at a node where all information is available (the "contained in" requirement). Among the possible nodes, it is most efficient to evaluate it as far down in the tree as possible. If it does not involve streams on both sides of the root of the subtree (qe), then it can be pushed further down (the "contains" requirement).