Classification problem

The Classification Problem in an area of science or mathematics is the problem of separating a large class of objects into smaller classes, and giving a criterion for determining whether a particular object is or is not in a particular class.

One of the most famous attempts at classification in biology is Linnaeus's famous classification of living things by class, order, genus, and species. In mathematics, one successful solution to a classification problem is the classification of vector spaces by their dimension. Two vector spaces are isomorphic if and only if they have the same dimension.