\CupThe \Cup operator represents the union of sets in set theory. It is used to denote the combination of all elements from two or more sets, without duplication.
Union of sets A and B
A \Cup BUnion of sets A, B, and C
(A \Cup B) \Cup CUnion of a sequence of sets A_i from i=1 to n
\bigcup_{i=1}^{n} A_i