AI 中文总结
本文证明可表示范畴中余紧对象为子终对象,并推广至无穷范畴,得出对偶可表示无穷范畴为小完备格,同时证明幻映射幂零性,并关联加强版本与可测基数存在性。
AI 中文摘要
我们给出了一个简短证明,表明在可表示范畴中,$\kappa$-余紧对象是子终对象。作为我们的主要结果,我们将此推广到可表示的$\infty$-范畴的设定中。一个推论是:若一个$\infty$-范畴$\mathcal{C}$及其对偶$\mathcal{C}^\mathsf{op}$都是可表示的,则$\mathcal{C}$是一个小完备格,这推广了Gabriel-Ulmer的经典定理。在此过程中,我们证明了一般点态可表示$\infty$-范畴中幻映射的幂零性结果。此外,我们表明,我们主要结果的一个加强版本等价于存在一个真类大小的可测基数。
英文摘要
We give a short proof that $κ$-cocompact objects in a presentable category are subterminal. As our main result, we extend this to the setting of presentable $\infty$-categories. A consequence is that an $\infty$-category $\mathcal{C}$ such that both $\mathcal{C}$ and $\mathcal{C}^\mathsf{op}$ are presentable is a small complete lattice, extending a classical theorem of Gabriel-Ulmer. Along the way, we prove a nilpotence result for phantom maps in general pointed presentable $\infty$-categories. Additionally, we show that a strengthening of our main result is equivalent to the existence of a proper class of measurable cardinals.
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