The collection of spaces that belong to a space group. The closure can be a ordered list or simply a collection of spaces.
For projectdoc a space closure is either a delegate space or a search space. A closure puts a collection of spaces in context. When we talk about the delegate space or the search space, we refer to the delegate space closure or the search space closure.
The delegate space allows to delegate the definition of space properties or homepages for doctypes. Therefore the order of the delegate space closure matters. When a Name List Macro checks for a matching document, it traverses the delegate space closure.
The search space closure defines a set of spaces that are taken into account when a search is conducted by a macro, such as the Display Table Macro.