Encyclopedia > Disjoint union

  Article Content

Disjoint union

In set theory, a disjoint union is a type of union (Set theoretic union), in which each element of the union is disjoint from the others: intersection with every other element of the union is the empty set.

i.e. Suppose C is a collection of sets, then:

<math>
\mathcal{A} = \bigcup_{A \in C} A </math>

is a disjoint union if and only if

<math>
\forall A,B \in C \quad st. \ A \ne B: A \cap B = \empty </math>

See also: Basic Set Theory



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Ocean Beach, New York

... under the age of 18, 5.1% from 18 to 24, 32.6% from 25 to 44, 31.2% from 45 to 64, and 9.4% who are 65 years of age or older. The median age is 42 years. For every 100 ...

 
 
 
This page was created in 30.3 ms