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\cup joins two sets. \bigcup is the large operator form that takes limits like \sum, for the union of a family of sets. The mnemonic is that \cup looks like a cup.
All ways to write it
| Command | Use | Package | Copy |
|---|---|---|---|
\cup | binary union | none | |
\bigcup_{i=1}^{n} | big operator with limits | none | |
\sqcup | disjoint union, ⊔ | none | |
\uplus | multiset union, ⊎ | none |
Example
A \cup B = \{x : x \in A \text{ or } x \in B\}, \qquad \bigcup_{n=1}^{\infty} A_nDefinition of union, and a countable union.
Questions
How do I remember \cup versus \cap?
\cup is shaped like a cup (∪) and \cap like a cap (∩).
Related symbols
- Intersection ∩
\cap - Subset ⊆
\subseteq - Element of ∈
\in - Empty set ∅
\emptyset
Using union in Confluence
Confluence Cloud has no built-in LaTeX. With LaTeX Math for Confluence you add a math macro to any page, type \cup and it renders inline or as a block, with a live preview while you edit. Every command on this page renders there without extra packages.