A relation is an partial-order if it is reflexive, asymmetric, and transitive.
(<=> (Partial-Order-Relation ?R) (And (Reflexive-Relation ?R) (Asymmetric-Relation ?R) (Transitive-Relation ?R)))
(Transitive-Relation ?R) (Asymmetric-Relation ?R) (Reflexive-Relation ?R)
(<=> (Partial-Order-Relation ?R) (And (Reflexive-Relation ?R) (Asymmetric-Relation ?R) (Transitive-Relation ?R))) (<=> (Total-Order-Relation ?R) (And (Partial-Order-Relation ?R) (=> (And (Instance-Of ?X (Exact-Domain ?R)) (Instance-Of ?Y (Exact-Domain ?R))) (Or (Holds ?R ?X ?Y) (Holds ?R ?Y ?X)))))