Definition:Inclusion Ordered Set

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

$\left({S, \preceq}\right)$ is inclusion ordered set
 * $\mathord\preceq = \mathord\subseteq \cap \left({S \times S}\right)$

That means,
 * $\forall x, y \in S: x \preceq y \iff x \subseteq y$