当前位置: X-MOL 学术J. Math. Log. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Degrees of categoricity and treeable degrees
Journal of Mathematical Logic ( IF 0.9 ) Pub Date : 2023-08-11 , DOI: 10.1142/s0219061324500028
Barbara F. Csima 1 , Dino Rossegger 2, 3
Affiliation  

In this paper, we give a characterization of the strong degrees of categoricity of computable structures greater or equal to 0. They are precisely the treeable degrees — the least degrees of paths through computable trees — that compute 0. As a corollary, we obtain several new examples of degrees of categoricity. Among them we show that every degree d with 0(α)d0(α+1) for α a computable ordinal greater than 2 is the strong degree of categoricity of a rigid structure. Using quite different techniques we show that every degree d with 0d0 is the strong degree of categoricity of a structure. Together with the above example this answers a question of Csima and Ng. To complete the picture we show that there is a degree d with 0<d<0 that is not the degree of categoricity of a rigid structure.



中文翻译:

分类度和可树度

在本文中,我们给出了可计算结构的强范畴度的表征,大于或等于0。它们正是可树度——通过可计算树的路径的最小度——计算0。作为推论,我们获得了几个新的类别度示例。其中我们表明每个度d0(αd0(α+1为了α可计算序数大于2是刚性结构的强范畴化程度。使用完全不同的技术,我们表明每个学位d0d0是结构的强范畴化程度。结合上面的例子,这就回答了 Csima 和 Ng 的问题。为了完成图片,我们表明有一个学位d0<d<0这不是刚性结构的范畴化程度。

更新日期:2023-08-12
down
wechat
bug