Set operations Definition: Let A and B be sets. The union of A and B, denoted by A B, is the set that contains those elements that are either in A or in B, or in both. • Alternate: A B = { x | x A x B }. • Example: • A = {1,2,3,6} B = { 2,4,6,9} • A B = { 1,2,3,4,6,9 } U A B CS 441 Discrete mathematics for CS M. Hauskrecht