Copying one of a pair of structures
Copying one of a pair of structures
复制标题
复制一对结构中的一个
DOI：
10.1017/jsl.2021.89
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Knight, Julia F.
中科院分区：
文献类型：
--
作者：
Alvir, Rachael;Burchfield, Hannah;Knight, Julia F.
我们问，对于一对结构，何时存在一个统一的有效程序，给定两个结构的副本，未标记，总是产生一个副本。我们给出了一些条件，保证有这样一个程序。这些条件可能表明，对于type和Harrison类型的排序对，不应该有任何这样的过程，但实际上有一个。我们构造一个示例，其中不存在这样的过程。施工涉及到强制。在构造示例的过程中，我们证明了关于修改Cohen泛型的一般结果。
We ask when, for a pair of structures , there is a uniform effective procedure that, given copies of the two structures, unlabeled, always produces a copy of . We give some conditions guaranteeing that there is such a procedure. The conditions might suggest that for the pair of orderings of type and of Harrison type, there should not be any such procedure, but, in fact, there is one. We construct an example for which there is no such procedure. The construction involves forcing. On the way to constructing our example, we prove a general result on modifying Cohen generics.