A D4: Binary relation ${\preceq} \subseteq X \times X$ on $X$ is a partial ordering relation on $X$ if and only if

(1)	$\forall \, x \in X : (x, x) \in {\preceq}$ (D287: Reflexive binary relation)
(2)	$\forall \, x, y, z \in X \, ((x, y), (y, z) \in {\preceq} \quad \implies \quad (x, z) \in {\preceq})$ (D288: Transitive binary relation)
(3)	$\forall \, x, y \in X \, ((x, y), (y, x) \in {\preceq} \quad \implies \quad x = y)$ (D289: Antisymmetric binary relation)