Kunen's inconsistency: Difference between revisions

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((Kunen's proof may not be generalizable to j : V_(λ+1) -> V_(λ+1), but what if something else is?))
 
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* For all limit cardinals \(\lambda\), there is no nontrivial elementary embedding \(j: V_{\lambda+2} \to V_{\lambda+2}\).
* For all limit cardinals \(\lambda\), there is no nontrivial elementary embedding \(j: V_{\lambda+2} \to V_{\lambda+2}\).


However, it is believed that it can not be generalized to show the nonexistence of a nontrivial elementary embedding \(j: V_{\lambda+1} \to V_{\lambda+1}\). Therefore, the rank-into-rank cardinals are believed to be inconsistent, but barely teetering on the brink of inconsistency.
However, it is believed that it can not be generalized to show the nonexistence of a nontrivial elementary embedding \(j: V_{\lambda+1} \to V_{\lambda+1}\). Therefore, the rank-into-rank cardinals are believed to be consistent, but barely teetering on the brink of inconsistency.


Kunen's inconsistency also implies that if \(\kappa\) is [[supercompact]], \(N\) is a [[Extender model|weak extender model]] for \(\kappa\)'s supercompactness, and \(j: N \to N\) is a nontrivial elementary embedding, then the critical point of \(j\) is less than \(\kappa\). It is known that there must be such an elementary embedding.
Kunen's inconsistency also implies that if \(\kappa\) is [[supercompact]], \(N\) is a [[Extender model|weak extender model]] for \(\kappa\)'s supercompactness, and \(j: N \to N\) is a nontrivial elementary embedding, then the critical point of \(j\) is less than \(\kappa\). It is known that there must be such an elementary embedding.