论文标题

$ p $ airpary封闭的字段中的可定义类型周围

Around definable types in $p$-adically closed fields

论文作者

Guerrero, Pablo Andujar, Johnson, Will

论文摘要

我们证明了$ p $ ofare封闭的字段中可定义类型的一些技术结果,对可定义的组和可定义的拓扑空间产生了影响。首先,可以将可定义的$ n $ type(在现场排序中)的代码视为真正的元组(在现场排序中),而不是虚构的元组(在几何术中)。其次,真实或虚构的任何可定义类型都是由值组参数化的可数链的可数联合生成的。第三,如果$ x $是可解释的集合,那么$ x $上的全球可定义类型的空间就是严格的专业解释,建立了Cobides Kovacsics,Hils和Ye的作品。第四,可以在可解释的冲销中(以非规范的方式)取消全局可定义的类型。第五,如果$ g $是一个可确定的f-generics($ dfg $)的可确定集团,而$ g $在可确定的套装$ x $上行动,那么商$ x/g $是可定义的,而不仅仅是可解释的。这解释了Pillay和Yao观察到的一些现象。最后,我们表明,可解释的拓扑空间满足了首次算法和曲线选择的类似物。利用这一点,我们表明,所有可定义的紧凑性的合理概念都符合可解释的拓扑空间,并且在家庭中可定义的紧凑性是可以定义的。

We prove some technical results on definable types in $p$-adically closed fields, with consequences for definable groups and definable topological spaces. First, the code of a definable $n$-type (in the field sort) can be taken to be a real tuple (in the field sort) rather than an imaginary tuple (in the geometric sorts). Second, any definable type in the real or imaginary sorts is generated by a countable union of chains parameterized by the value group. Third, if $X$ is an interpretable set, then the space of global definable types on $X$ is strictly pro-interpretable, building off work of Cubides Kovacsics, Hils, and Ye. Fourth, global definable types can be lifted (in a non-canonical way) along interpretable surjections. Fifth, if $G$ is a definable group with definable f-generics ($dfg$), and $G$ acts on a definable set $X$, then the quotient space $X/G$ is definable, not just interpretable. This explains some phenomena observed by Pillay and Yao. Lastly, we show that interpretable topological spaces satisfy analogues of first-countability and curve selection. Using this, we show that all reasonable notions of definable compactness agree on interpretable topological spaces, and that definable compactness is definable in families.

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