The finer groupings beneath a major category, such as the branch of mathematics a theorem belongs to or the historical era a mathematician worked in, one entity per grouping label so its own page can carry a description of what belongs in that narrower slice. Belongs here: the subcategory nodes themselves, the branch, concept, conjecture, theorem, mathematician and article clusters and eras. Does not belong here: the mathematicians, theorems, concepts and other subjects a subcategory groups, filed under their own type and reached through the subcategory's own member listing.