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arXiv 2209.04082math.LO
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二阶算术中的决定性与反射原理

Determinacy and reflection principles in second-order arithmetic

Leonardo Pacheco, Keita Yokoyama

AI总结:

本文在二阶算术中证明了决定性公理变体与反射原理之间的等价关系,扩展了Kołodziejczyk和Michalewski的结果,并重述了Montalbán和Shore的相关研究。

摘要:

已知决定性公理的若干变体在反推数学研究中发挥重要作用,Tanaka、Nemoto、Montalbán、Shore等人揭示了决定性层级与概括公理之间的关系。我们证明了Kołodziejczyk和Michalewski关于$Σ^0_2$集合的任意布尔组合的决定性与二阶算术中反射之间联系的结果的变体。具体而言,我们证明:在$\mathsf{ACA}_0$之上,$Π^1_2$-$\mathsf{Ref}(\mathsf{ACA}_0)$等价于$\forall n.(Σ^0_1)_n$-$\mathsf{Det}^*_0$;$Π^1_3$-$\mathsf{Ref}(Π^1_1$-$\mathsf{CA}_0)$等价于$\forall n.(Σ^0_1)_n$-$\mathsf{Det}$;且$Π^1_3$-$\mathsf{Ref}(Π^1_2$-$\mathsf{CA}_0)$等价于$\forall n.(Σ^0_2)_n$-$\mathsf{Det}$。我们还重述了Montalbán和Shore的结果,以表明在$\mathsf{ACA}_0$之上,$Π^1_3$-$\mathsf{Ref}(\mathsf{Z}_2)$等价于$\forall n.(Σ^0_3)_n$-$\mathsf{Det}$。

英文摘要:

It is known that several variations of the axiom of determinacy play important roles in the study of reverse mathematics, and the relation between the hierarchy of determinacy and comprehension are revealed by Tanaka, Nemoto, Montalbán, Shore, and others. We prove variations of a result by Kołodziejczyk and Michalewski relating determinacy of arbitrary boolean combinations of $Σ^0_2$ sets and reflection in second-order arithmetic. Specifically, we prove that: over $\mathsf{ACA}_0$, $Π^1_2$-$\mathsf{Ref}(\mathsf{ACA}_0)$ is equivalent to $\forall n.(Σ^0_1)_n$-$\mathsf{Det}^*_0$; $Π^1_3$-$\mathsf{Ref}(Π^1_1$-$\mathsf{CA}_0)$ is equivalent to $\forall n.(Σ^0_1)_n$-$\mathsf{Det}$; and $Π^1_3$-$\mathsf{Ref}(Π^1_2$-$\mathsf{CA}_0)$ is equivalent to $\forall n.(Σ^0_2)_n$-$\mathsf{Det}$. We also restate results by Montalbán and Shore to show that $Π^1_3$-$\mathsf{Ref}(\mathsf{Z}_2)$ is equivalent to $\forall n.(Σ^0_3)_n$-$\mathsf{Det}$ over $\mathsf{ACA}_0$.

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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