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:
“My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave, I would do it; and if I could save it by freeing all the slaves, I would do it; and if I could save it by freeing some and leaving others alone, I would also do that.”
—Abraham Lincoln (1809–1865)