## Ideal (Partial Order)

An ideal of a Partial Order is a subset of the elements of which satisfy the property that if and , then . For disjoint chains in which the th chain contains elements, there are ideals. The number of ideals of a -element Fence Poset is the Fibonacci Number .

References

Ruskey, F. Information on Ideals of Partially Ordered Sets.'' http://sue.csc.uvic.ca/~cos/inf/pose/Ideals.html.

Steiner, G. An Algorithm to Generate the Ideals of a Partial Order.'' Operat. Res. Let. 5, 317-320, 1986.