An embodiment of the present invention provides a method of applying a set function on documents in an axis-based interface, the method comprising grouping a plurality of documents in a plurality of axes of documents, the documents from each axis of documents having commonality, grouping a plurality of axes of documents in a group of axes of documents, the documents from the group of axes of documents being disposed along a collation function, wherein at least some of the axes of documents are adapted to be used by a set function adapted to mathematically collectively manipulate documents thereof. Groups of axes of documents are also adapted to be used by a set function adapted to mathematically collectively manipulate documents thereof.