Keisler’s order has infinitely many classes
نویسندگان
چکیده
منابع مشابه
Keisler’s Order Has Infinitely Many Classes
We prove, in ZFC, that there is an infinite strictly descending chain of classes of theories in Keisler’s order. Thus Keisler’s order is infinite and not a well order. Moreover, this chain occurs within the simple unstable theories, considered model-theoretically tame. Keisler’s order is a central notion of the model theory of the 60s and 70s which compares first-order theories (and implicitly ...
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ژورنال
عنوان ژورنال: Israel Journal of Mathematics
سال: 2018
ISSN: 0021-2172,1565-8511
DOI: 10.1007/s11856-018-1647-7