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arXiv 2006.01077math.LO
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ZF与从$V_{λ+2}$到$V_{λ+2}$的初等嵌入一致性的研究

On the consistency of ZF with an elementary embedding from $V_{λ+2}$ into $V_{λ+2}$

Farmer Schlutzenberg

AI总结:

本文在ZF下证明,若$I_{0,λ}$成立且$λ$为偶数,则存在包含$V_{λ+1}$的内模型满足ZF及存在从$V_{λ+2}$到自身的初等嵌入,并探讨了相关大基数公理的一致性后果。

摘要:

根据Kenneth Kunen的一个定理,在ZFC下,不存在序数$λ$和非平凡的初等嵌入$j:V_{λ+2}\to V_{λ+2}$。他的证明依赖于选择公理(AC),而仅从ZF出发的证明尚未被发现。\n$I_{0,λ}$是由W. Hugh Woodin引入的断言,即$λ$是一个序数,并且存在一个初等嵌入$j:L(V_{λ+1})\to L(V_{λ+1})$,其临界点小于$λ$。而$I_0$断言对于某个$λ$,$I_{0,λ}$成立。公理$I_0$是已知不与AC矛盾的最强的大基数之一。通常在全宇宙$V$中假设ZFC来研究它(在这种情况下$λ$必须是极限序数),但我们仅假设ZF。\n我们证明,在ZF + $I_{0,λ}$ + “$λ$是偶数”的假设下,存在一个包含$V_{λ+1}$的传递真类内模型$M$,满足ZF + $I_{0,λ}$ + “存在初等嵌入$k:V_{λ+2}\to V_{λ+2}$”;实际上我们将有$k\subseteq j$,其中$j$在$M$中见证$I_{0,λ}$。这一结果最初由作者在额外假设$V_{λ+1}^\\#$存在的情况下证明;Gabe Goldberg注意到这个额外假设是不必要的。如果$λ$也是极限序数且$λ$-DC在$V$中成立,那么模型$M$也将满足$λ$-DC。\n我们证明ZFC + “$λ$是偶数” + $I_{0,λ}$蕴含对于每个$A\in V_{λ+1}$,$A^\\#$存在,但如果一致,这个理论并不蕴含$V_{λ+1}^\\#$存在。

英文摘要:

According to a theorem due to Kenneth Kunen, under ZFC, there is no ordinal $λ$ and non-trivial elementary embedding $j:V_{λ+2}\to V_{λ+2}$. His proof relied on the Axiom of Choice (AC), and no proof from ZF alone has been discovered. $I_{0,λ}$ is the assertion, introduced by W. Hugh Woodin, that $λ$ is an ordinal and there is an elementary embedding $j:L(V_{λ+1})\to L(V_{λ+1})$ with critical point ${<λ}$. And $I_0$ asserts that $I_{0,λ}$ holds for some $λ$. The axiom $I_0$ is one of the strongest large cardinals not known to be inconsistent with AC. It is usually studied assuming ZFC in the full universe $V$ (in which case $λ$ must be a limit ordinal), but we assume only ZF. We prove, assuming ZF + $I_{0,λ}$ + "$λ$ is an even ordinal", that there is a proper class transitive inner model $M$ containing $V_{λ+1}$ and satisfying ZF + $I_{0,λ}$ + "there is an elementary embedding $k:V_{λ+2}\to V_{λ+2}$"; in fact we will have $k\subseteq j$, where $j$ witnesses $I_{0,λ}$ in $M$. This result was first proved by the author under the added assumption that $V_{λ+1}^\#$ exists; Gabe Goldberg noticed that this extra assumption was unnecessary. If also $λ$ is a limit ordinal and $λ$-DC holds in $V$, then the model $M$ will also satisfy $λ$-DC. We show that ZFC + "$λ$ is even" + $I_{0,λ}$ implies $A^\#$ exists for every $A\in V_{λ+1}$, but if consistent, this theory does not imply $V_{λ+1}^\#$ exists.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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