论文标题

扩展逻辑的内部模型:第1部分

Inner Models from Extended Logics: Part 1

论文作者

Kennedy, Juliette, Magidor, Menachem, Väänänen, Jouko

论文摘要

如果我们在Gödel的内部模型$ L $的原始定义中替换为二阶逻辑,我们将获得HOD。在本文中,我们考虑如果我们替换一阶逻辑替换为具有二阶逻辑强度但不是全部的逻辑,就会出现的内部模型。典型的示例是通用量词的一阶逻辑扩展,例如Magidor-Malitz量词,Cofinality量词或固定逻辑。我们的第一组结果表明,$ L $和HOD都表现出一定数量的{\ em形式主义freeness},因为它们对选择基础逻辑的选择不太敏感。我们的第二组结果表明,Cofinality量化器在$ L $和HOD之间产生了一个新的健壮内部模型。除其他外,我们还表明,假设伍丁红衣主教的适当类别的常规红衣主教$> \ aleph_1 $ $ v $在内部模型中是弱紧凑的,这是由辅助量化器引起的,该模型的理论(集合)是绝对的,强迫绝对且独立于所涉及的辅助性。我们不知道该模型是否满足连续性假设,假设是大型的红衣主教,但是我们可以表明,假设三个木质枢机主教和一个可测量的枢机主教,则如果将构造相关与真实的构造相关,那么在真实的锥上,连续假设在相关模型中是正确的。

If we replace first order logic by second order logic in the original definition of Gödel's inner model $L$, we obtain HOD. In this paper we consider inner models that arise if we replace first order logic by a logic that has some, but not all, of the strength of second order logic. Typical examples are the extensions of first order logic by generalized quantifiers, such as the Magidor-Malitz quantifier, the cofinality quantifier, or stationary logic. Our first set of results show that both $L$ and HOD manifest some amount of {\em formalism freeness} in the sense that they are not very sensitive to the choice of the underlying logic. Our second set of results shows that the cofinality quantifier gives rise to a new robust inner model between $L$ and HOD. We show, among other things, that assuming a proper class of Woodin cardinals the regular cardinals $>\aleph_1$ of $V$ are weakly compact in the inner model arising from the cofinality quantifier and the theory of that model is (set) forcing absolute and independent of the cofinality in question. We do not know whether this model satisfies the Continuum Hypothesis, assuming large cardinals, but we can show, assuming three Woodin cardinals and a measurable above them, that if the construction is relativized to a real, then on a cone of reals the Continuum Hypothesis is true in the relativized model.

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