partial order: if
strict partial orders: a relation < that is irreflexive, asymmetric, and transitive on a set
quasi-order: also sometimes called a preorder, if ⪯ is a reflexive, transitive relation on 𝑆. 对应于中文的拟序关系。
拟序是一个并不太常见的关系。整除关系是一个拟序关系,满足自反性和传递性。但是不满足反对称性,(
严格偏序关系是特殊的偏序关系,偏序关系是特殊的拟序关系。