Let $\mathsf{LB} = \mathsf{LB}_P(E)$ be the D553: Set of lower bounds of $E \subseteq X$ with respect to $P$.
A D2218: Set element $x_0 \in X$ is an infimum of $E$ with respect to $P$ if and only if
| (1) | $x_0 \in \mathsf{LB}$ |
| (2) | $\forall \, x \in \mathsf{LB} : (x, x_0) \in {\preceq}$ |