In mathematics, the term disjoint union may refer to one of two different but related concepts:
- In set theory, the disjoint union (or discriminated union) of a family of sets is a modified union operation that indexes the elements according to which set they originated in; disjoint sets have no element in common.
- When one says that a set is the disjoint union of a family of subsets, this means that it is the union of the subsets and that the subsets are pairwise disjoint.
Read more about Disjoint Union: Set Theory Definition, Category Theory Point of View
Famous quotes containing the word union:
“Our age is pre-eminently the age of sympathy, as the eighteenth century was the age of reason. Our ideal men and women are they, whose sympathies have had the widest culture, whose aims do not end with self, whose philanthropy, though centrifugal, reaches around the globe.”
—Frances E. Willard 1839–1898, U.S. president of the Women’s Christian Temperance Union 1879-1891, author, activist. The Woman’s Magazine, pp. 137-40 (January 1887)