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第20章 莱茵哈特基数(英)
A cardinal κ is Reinhardt if there is an elementary embedding
j : V → V
with critical point κ.
Theorem (Kunen, 1971)
ZFC implies that Reinhardt cardinals don’t exist. In fact, there is
no non-trivial elementary embedding
j : Vλ+2 → Vλ+2
Definition
κ is super Reinhardt if for all ordinals λ there exists a non-trivial
elementary embedding j : V → V such that crit(j)=κ and
j(κ)>λ.
If A is a proper class, then κ is A -super Reinhardt if for all ordinals
λ there exists a non-trivial elementary embedding j : V → V such
that crit(j)=κ, j(κ)>λ, and j(A)= A, where
j(A):= S
α∈OR j(A ∩ Vα).
κ is totally Reinhardt if for each A ∈ Vκ+1,
hVκ, Vκ+1i |= ZF2 +“There is an A -super Reinhardt cardinal”