Annals of Pure and Applied Logic ( IF 0.6 ) Pub Date : 2021-04-29 , DOI: 10.1016/j.apal.2021.102988 William Chan , Stephen Jackson
Assume . Let ≈ denote the relation of being in bijection. Let and be such that for all , is an equivalence relation on with all classes countable and . Then the disjoint union is in bijection with and has the Jónsson property.
Assume . A set has a sequence of equivalence relations on such that and if and only if injects into X.
Assume . Suppose is a relation such that for all , is nonempty and countable. Then there is an uncountable and function which uniformizes R on : that is, for all , .
Under , if κ is an ordinal and is a sequence of equivalence relations on with all classes countable, then does not inject into .
中文翻译:
光滑对等关系的商的有序不相交并的基数
认为 。让≈表示存在双射的关系。让 和 对所有人来说 , 是上的等价关系 所有班级都是可数的 。然后是脱节的联合 与 和 拥有Jónsson属性。
认为 。一套 有一个序列 等价关系 这样 和 当且仅当 注入到X。
认为 。认为 是这样的关系,对于所有人 , 是非空且可数的。然后有一个不可数的 和功能 使R on均匀化:也就是说,对于所有人 , 。
在下面 ,如果κ是序数且 是一个等价关系的序列 所有班级都是可数的,那么 不注入 。