In his seminal paper introducing the fine structure of L, Jensen (Ann Math Log 4:229–308, 1972) proved that under \(V=L\) any regular cardinal that reflects stationary sets is weakly compact. In this paper we give a new proof of Jensen’s result that is straight-forward and accessible to those without a knowledge of Jensen’s fine structure theory. The proof here instead uses hyperfine structure, a very natural and simpler alternative to fine structure theory introduced by Friedman and Koepke (Bull Symb Log 3:453–468, 1997).

中文翻译：

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非弱紧凑基数下方的正方形

Jensen在其开创性的论文中介绍了L的精细结构（Ann Math Log 4：229–308，1972）证明，在（（V = L \））下，任何能反映平稳集的规则基数都是弱紧致的。在本文中，我们为Jensen的结果提供了新的证明，该证明简单明了，可供那些不了解Jensen精细结构理论的人使用。相反，这里的证明使用超精细结构，这是Friedman和Koepke提出的精细结构理论的一种非常自然和简单的替代方法（Bull Symb Log 3：453–468，1997）。