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
|
The object union is a method function.