# Definition:Dedekind Complete Set

## Definition

Let $\left({S, \preceq}\right)$ be an ordered set.

Then $\left({S, \preceq}\right)$ is **Dedekind complete** if and only if every non-empty subset of $S$ that is bounded above admits a supremum (in $S$).

## Also known as

This is commonly referred to as:

- the
**supremum property** - the
**least upper bound property** - the
**infimum property** - the
**greatest lower bound property**

where the latter denominations are justified by Dedekind Completeness is Self-Dual.

Some sources hyphenate: **Dedekind-complete**. In the interest of consistency, $\mathsf{Pr} \infty \mathsf{fWiki}$ prefers the non-hyphenated version.

## Also see

- Results about
**Dedekind complete sets**can be found here.

## Source of Name

This entry was named for Julius Wilhelm Richard Dedekind.

## Sources

- 2000: James R. Munkres:
*Topology*(2nd ed.) ... (previous) ... (next): $1$: Set Theory and Logic: $\S 3$: Relations