Written by M Yass, Joe Zeng, alexei, et al. last updated
Requires: Set

The union of two sets and , denoted , is the set of things which are either in or in or both.

illustration of the output of the union operation

Formally stated, where

That is, Iff is in the union , then either is in or or possibly both.

Examples

  • (In other words, the union of the negative reals, the positive reals and zero make up all of the real numbers.)