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Proceedings of the American Mathematical Society
Proceedings of the American Mathematical Society
ISSN 1088-6826 (e) ISSN 0002-9939 (p)
     

Any behaviour of the Mitchell ordering of normal measures is possible

Author(s): Jirí Witzany
Journal: Proc. Amer. Math. Soc. 124 (1996), 291-297.
MSC (1991): Primary 03E35, 03E55
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Abstract: Let $U_0,U_1$ be two normal measures on $\kappa $. We say that $U_0$ is in the Mitchell ordering less than $U_1,$ $U_0\vartriangleleft U_1,$ if $U_0 \in \mathrm{Ult}(V,U_1) .$ The relation is well-known to be transitive and well-founded. It has been an open problem to find a model where $\vartriangleleft $ embeds the four-element poset \includegraphics{proc3019e-fig-a} . We find a generic extension where all well-founded posets are embeddable. Hence there is no structural restriction on the Mitchell ordering. Moreover we show that it is possible to have two $\vartriangleleft $-incomparable measures that extend in a generic extension into two $\vartriangleleft $-comparable measures.


References:

Ba85
S. Baldwin, The $\vartriangleleft $-ordering on normal ultrafilters, J. Symbolic Logic 51 (1985), 936--952, MR 87d:03124.

Cu93
J. Cummings, Possible behaviors for the Mitchell ordering, Ann. Pure Appl. Logic (to appear).

KuP71
K. Kunen and J. B. Paris, Boolean extensions and measurable cardinals, Ann. of Math. Logic 2 (1971), 359--377, MR 43:3114.

Mi83
W.J. Mitchell, Sets constructible from sequences of measures: revisited, J. Symbolic Logic 48 (1983), 600--609, MR 85j:03052.

W94a
J. Witzany, Possible behaviours of the reflection ordering of stationary sets, J. Symbolic Logic (to appear).

W94b
J. Witzany, Reflection of stationary sets and the Mitchell ordering of normal measures, Ph.D. thesis, Pennsylvania State University, 1994.


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Additional Information:

DOI: 10.1090/S0002-9939-96-03019-5
PII: S 0002-9939(96)03019-5
Keywords: Stationary sets, reflection, measurable cardinals, repeat points
Communicated by: \commby Andreas R. Blass
Copyright of article: Copyright 1996, American Mathematical Society


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