Definition:Disjoint Union (Set Theory)/Also known as

Disjoint Union: Also known as

A disjoint union in the context of set theory is also called a discriminated union.

In Georg Cantor's original words:

We denote the uniting of many aggregates $M, N, P, \ldots$, which have no common elements, into a single aggregate by

$\tuple {M, N, P, \ldots}$.

The elements in this aggregate are, therefore, the elements of $M$, of $N$, of $P$, $\ldots$, taken together.

Sources

• 1915: Georg Cantor: Contributions to the Founding of the Theory of Transfinite Numbers ... (previous) ... (next): First Article: $\S 1$: The Conception of Power or Cardinal Number: $(2)$