Union: Difference between revisions
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imported>Mirzhan Irkegulov m (Primitive stub made. Math specialists, please improve (=) |
imported>Richard Pinch (see also: Disjoint union) |
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===Finite unions=== | ===Finite unions=== | ||
===Infinite unions=== | ===Infinite unions=== | ||
==See also== | |||
* [[Disjoint union]] | |||
Revision as of 13:46, 4 November 2008
In set theory, union (denoted as ∪) is a set operation between two sets that forms a set containing the elements of both sets.
Formally, union A ∪ B means that if a ∈ A ∪ B, then a ∈ A ∨ a ∈ B, where ∨ - is logical or. We see this connection between ∪ and ∨ symbols.
Union operation is:
- associative - (A ∪ B) ∪ C = A ∪ (B ∪ C)
- commutative - A ∪ B = B ∪ A.