The focus of topology here is the study of the subset structure of sets in the mathematical spaces. Topology can be used to describe and relate the different spaces used in niche modeling. A topology is a natural internal structure, precisely defining the entire group of subsets produced by standard operations of union and intersection. Of particular importance are those subsets, referred to as open sets, where every element has a neighborhood also in the set. More than one topology in X may be possible for a given set X.