Archive For Mathematical Logic ( IF 0.4 ) Pub Date : 2021-02-06 , DOI: 10.1007/s00153-021-00760-z Ricardo Isaac Bello Aguirre
We study ultraproducts of finite residue rings \(\prod \nolimits _{n\in {\mathbb {N}}} {\mathbb {Z}}/n{\mathbb {Z}}\diagup {\mathcal {U}} \) where \({\mathcal {U}}\) is a non-principal ultrafilter. We find sufficient conditions of the ultrafilter \({\mathcal {U}}\) to determine if the resulting ultraproduct \(\prod \nolimits _{n\in {\mathbb {N}}} {\mathbb {Z}}/n{\mathbb {Z}}\diagup {\mathcal {U}}\) has simple, NIP, \(\mathrm {NTP}_{2}\) but not simple nor NIP, or \(\mathrm {TP}_{2}\) theory, noting that all these four cases occur.
中文翻译:
有限残环超产品的广义稳定性
我们研究有限剩余环的超积\(\ prod \ nolimits _ {n \ in {\ mathbb {N}}} {\ mathbb {Z}} / n {\ mathbb {Z}} \ diagup {\ mathcal {U} } \)其中\({\ mathcal {U}} \)是非主要的超滤镜。我们找到超滤子\({\ mathcal {U}} \)的充分条件,以确定所得的超产品\(\ prod \ nolimits _ {n \ in {\ mathbb {N}}} {\ mathbb {Z}} / n {\ mathbb {Z}} \ diagup {\ mathcal {U}} \)具有简单,NIP,\(\ mathrm {NTP} _ {2} \),但不是简单,NIP或\(\ mathrm { TP} _ {2} \)理论,请注意这四种情况均会发生。