# union -- computes the union of two posets

## Synopsis

• Usage:
R = union(P, Q)
R = P + Q
• Inputs:
• P, an instance of the type Poset,
• Q, an instance of the type Poset,
• Outputs:
• R, an instance of the type Poset, the union of $P$ and $Q$

## Description

The union of two posets is the poset induced by the union of the ground sets and the covering relations.

 i1 : union(chain 3, poset {{1,4},{4,5},{5,3}}) o1 = Relation Matrix: | 1 1 1 1 1 | | 0 1 1 0 0 | | 0 0 1 0 0 | | 0 0 1 1 1 | | 0 0 1 0 1 | o1 : Poset