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There's no forcing a least upper bound


Author: Robert S. Lubarsky
Journal: Proc. Amer. Math. Soc. 105 (1989), 998-1002
MSC: Primary 03E40; Secondary 03E45
DOI: https://doi.org/10.1090/S0002-9939-1989-0943796-8
MathSciNet review: 943796
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Abstract: While it is possible to have an increasing $ \omega $-sequence of $ c$-degrees with a least upper bound in a particular model of ZF, we show that it is not possible to force a sequence with a least upper bound absolute among all generic extensions of the original model


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Additional Information

DOI: https://doi.org/10.1090/S0002-9939-1989-0943796-8
Keywords: Degree of constructibility, forcing
Article copyright: © Copyright 1989 American Mathematical Society